UNDERWRITING AGREEMENT

Exhibit 1.3

25,000,000 Shares

DYNCORP INTERNATIONAL INC.

Class A Common Stock

UNDERWRITING AGREEMENT

May [    ], 2006            

C REDIT S UISSE S ECURITIES (USA) LLC

G OLDMAN , S ACHS  & C O .

As Representatives of the Several Underwriters,

c/o Credit Suisse Securities (USA) LLC,

Eleven Madison Avenue,

New York, N.Y. 10010-3629

Dear Sirs:

1. Introductory . DynCorp International Inc., a Delaware corporation (the “ Company ”) proposes to issue and sell 25,000,000 shares of its Class A common stock (“ Securities ”) (such 25,000,000 shares of Securities being hereinafter referred to as the “ Firm Securities ”). The Company also proposes to issue and sell to the Underwriters, at the option of the Underwriters, not more than 3,750,000 additional outstanding shares of the Company’s Securities, as set forth below (such 3,750,000 additional shares being hereinafter referred to as the “ Optional Securities ”). The Firm Securities and the Optional Securities are herein collectively called the “ Offered Securities .” As part of the offering contemplated by this Agreement, Credit Suisse Securities (USA) LLC (the “ Designated Underwriter ”) has agreed to reserve out of the Firm Securities purchased by it under this Agreement, up to 1,250,000 shares, for sale to the Company’s directors, officers, employees and other parties associated with the Company (collectively, “ Participants ”), as set forth in the Prospectus (as defined herein) under the heading “Underwriting” (the “ Directed Share Program ”). The Firm Securities to be sold by the Designated Underwriter pursuant to the Directed Share Program (the “ Directed Shares ”) will be sold by the Designated Underwriter pursuant to this Agreement at the public offering price. Any Directed Shares not subscribed for by the end of the business day on which this Agreement is executed will be offered to the public by the Underwriters as set forth in the Prospectus. The Company hereby agrees with Credit Suisse Securities (USA) LLC and Goldman, Sachs & Co. as representatives (together, the “ Representatives ”) of the several underwriters named in Schedule A hereto (“ Underwriters ”) as follows:

2. Representations and Warranties of the Company . The Company represents and warrants to, and agrees with, the several Underwriters that:

(i) A registration statement (No. 333-128637) (“ initial registration statement ”) relating to the Offered Securities, including a form of prospectus, has been filed with the Securities and Exchange Commission (“ Commission ”) and an additional registration statement (“ additional registration statement ”) relating to the Offered Securities may have been or may be filed with the Commission pursuant to Rule 462(b) (“ Rule 462(b) ”) under the Securities Act of 1933 (“ Act ”). “ Initial Registration Statement ” as of any time means the initial registration statement, in the form then filed with the Commission, including all information contained in the additional registration statement (if any) and then deemed to be a part of the initial registration statement pursuant to the General Instructions of the Form on which it is filed and all information (if any) included in a prospectus then deemed to be a part of the initial registration statement pursuant to Rule 430C (“ Rule 430C ”) under the Act or retroactively deemed to be a part of the initial registration statement pursuant to Rule 430A(b) (“ Rule 430A(b) ”) under the Act and that in any case has not then been superseded or modified. “ Additional Registration Statement ” as of any time means the additional registration statement, in the form then filed with the Commission, including the

contents of the Initial Registration Statement incorporated by reference therein and including all information (if any) included in a prospectus then deemed to be a part of the additional registration statement pursuant to Rule 430C or retroactively deemed to be a part of the additional registration statement pursuant to Rule 430A(b) and that in any case has not then been superseded or modified. The Initial Registration Statement and the Additional Registration Statement are herein referred to collectively as the “ Registration Statements ” and individually as a “ Registration Statement ”. “ Registration Statement ” as of any time means the Initial Registration Statement and any Additional Registration Statement as of such time. For purposes of the foregoing definitions, information contained in a form of prospectus that is deemed retroactively to be a part of a Registration Statement pursuant to Rule 430A shall be considered to be included in such Registration Statement as of the time specified in Rule 430A. As of the time of execution and delivery of this Agreement, the Initial Registration Statement has been declared effective under the Act and is not proposed to be amended. Any Additional Registration Statement has or will become effective upon filing with the Commission pursuant to Rule 462(b) and is not proposed to be amended. The Offered Securities all have been or will be duly registered under the Act pursuant to the Initial Registration Statement and, if applicable, the Additional Registration Statement. For purposes of this Agreement, “ Effective Time ” with respect to the Initial Registration Statement or, if filed prior to the execution and delivery of this Agreement, the Additional Registration Statement means the date and time as of which such Registration Statement was declared effective by the Commission or has become effective upon filing pursuant to Rule 462(c) (“ Rule 462(c) ”) under the Act. If an Additional Registration Statement has not been filed prior to the execution and delivery of this Agreement but the Company has advised the Representatives that it proposes to file one, “ Effective Time ” with respect to such Additional Registration Statement means the date and time as of which such Registration Statement is filed and becomes effective pursuant to Rule 462(b). “ Effective Date ” with respect to the Initial Registration Statement or the Additional Registration Statement (if any) means the date of the Effective Time thereof. A “ Registration Statement ” without reference to a time means such Registration Statement as of its Effective Time. “ Statutory Prospectus ” as of any time means the prospectus included in a Registration Statement immediately prior to that time, including any information in a prospectus deemed to be a part thereof pursuant to Rule 430A or 430C that has not been superseded or modified. For purposes of the preceding sentence, information contained in a form of prospectus that is deemed retroactively to be a part of a Registration Statement pursuant to Rule 430A shall be considered to be included in the Statutory Prospectus as of the actual time that form of prospectus is filed with the Commission pursuant to Rule 424(b) (“ Rule 424(b) ”) under the Act. “ Prospectus ” means the Statutory Prospectus that discloses the public offering price and other final terms of the Offered Securities and otherwise satisfies Section 10(a) of the Act. “ Issuer Free Writing Prospectus ” means any “issuer free writing prospectus,” as defined in Rule 433, relating to the Offered Securities in the form filed or required to be filed with the Commission or, if not required to be filed, in the form retained in the Company’s records pursuant to Rule 433(g). “ General Use Issuer Free Writing Prospectus ” means any Issuer Free Writing Prospectus that is intended for general distribution to prospective investors, as evidenced by its being specified on Schedule B to this Agreement. “ Limited Use Issuer Free Writing Prospectus ” means any Issuer Free Writing Prospectus that has been consented to by the Company in accordance with Section 6 hereto and that is not a General Use Issuer Free Writing Prospectus. “ Applicable Time ” means [                      ]:00 [a/p]m (Eastern time) on the date of this Agreement.

(ii) (A) On the Effective Date of the Initial Registration Statement, the Initial Registration Statement conformed in all material respects to the requirements of the Act and the rules and regulations of the Commission (“ Rules and Regulations ”) and did not include any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary to make the statements therein not misleading, (B) on the Effective Date of the Additional Registration Statement (if any), each Registration Statement conformed or will conform, in all material respects to the requirements of the Act and the Rules and Regulations and did not include, or will not include, any untrue statement of a material fact and did not omit, or will not omit, to state any material fact required to be stated therein or necessary to make the statements therein not misleading, and (C) on the date of this Agreement, the Initial Registration Statement and, if the Effective Time of the Additional Registration Statement is prior to the execution and delivery of this Agreement, the Additional Registration Statement (if any) each conforms, and at the time of filing of the Prospectus pursuant to Rule 424(b) or (if no such filing is required) at the Effective Date of the Additional Registration Statement in which the Prospectus is included, each Registration Statement and the

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Prospectus will conform, in all material respects to the requirements of the Act and the Rules and Regulations, and neither of such documents includes, or will include, any untrue statement of a material fact or omits, or will omit, to state any material fact required to be stated therein or necessary to make the statements therein not misleading. The preceding sentence does not apply to statements in or omissions from a Registration Statement or the Prospectus based upon written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information is that described as such in Section 8(b) hereof.

(iii) At the time of the initial filing of the Initial Registration Statement and (ii) at the date of this Agreement, the Company was not and is not an “ineligible issuer,” as defined in Rule 405.

(iv) As of the Applicable Time, neither (i) the General Use Issuer Free Writing Prospectus(es) issued at or prior to the Applicable Time, the preliminary prospectus dated April 17, 2006 (which is the most recent Statutory Prospectus distributed to investors generally), and the price to the public on the cover page of the Prospectus and the statements under the caption “Description of Capital Stock” in the Prospectus, all considered together (collectively, the “ General Disclosure Package ”), nor (ii) any individual Limited Use Issuer Free Writing Prospectus, when considered together with the General Disclosure Package, included any untrue statement of a material fact or omitted to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The preceding sentence does not apply to statements in or omissions from any prospectus included in the Registration Statement or any Issuer Free Writing Prospectus in reliance upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in Section 8(b) hereof.

(v) Each Issuer Free Writing Prospectus, as of its issue date and at all subsequent times through the completion of the public offer and sale of the Offered Securities or until any earlier date that the Company notified or notifies Credit Suisse as described in the next sentence, did not, does not and will not include any information that conflicted, conflicts or will conflict with the information then contained in the Registration Statement. If at any time following issuance of an Issuer Free Writing Prospectus there occurred or occurs an event or development as a result of which such Issuer Free Writing Prospectus conflicted or would conflict with the information then contained in the Registration Statement or included or would include an untrue statement of a material fact or omitted or would omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances prevailing at that subsequent time, not misleading, (i) the Company has promptly notified or will promptly notify Credit Suisse and (ii) the Company has promptly amended or will promptly amend or supplement such Issuer Free Writing Prospectus to eliminate or correct such conflict, untrue statement or omission. The foregoing two sentences do not apply to statements in or omissions from any Issuer Free Writing Prospectus in reliance upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in Section 8(b) hereof.

(vi) The Company has been duly incorporated and is an existing corporation in good standing under the laws of the State of Delaware, with power and authority (corporate and other) to own its properties and conduct its business as described in the General Disclosure Package; and the Company is duly qualified to do business as a foreign corporation in good standing in all other jurisdictions in which its ownership or lease of property or the conduct of its business requires such qualification, except where the failure to be so qualified or in good standing in any such jurisdiction would not individually or in the aggregate, result in a material adverse effect on the condition (financial or other), business, properties or results of operations of the Company and its subsidiaries taken as a whole (“ Material Adverse Effect ”).

(vii) Each subsidiary of the Company has been duly incorporated or formed, as the case may be, and is an existing corporation or limited liability company, as the case may be, in good standing under the laws of the jurisdiction of its incorporation or formation, as the case may be, with power and authority (corporate and other) to own its properties and conduct its business as described in the General Disclosure Package; and each subsidiary of the Company is duly qualified to do business as a foreign corporation or

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limited liability company in good standing in all other jurisdictions in which its ownership or lease of property or the conduct of its business requires such qualification; except where the failure to be so qualified or in good standing in any such jurisdiction would not individually or in the aggregate, result in a Material Adverse Effect; all of the issued and outstanding capital stock or membership interests, as the case may be, of each subsidiary of the Company has been duly authorized and validly issued and is fully paid and nonassessable; and the capital stock or membership interests, as the case may be, of each subsidiary owned by the Company, directly or through subsidiaries, is owned free from liens, encumbrances and defects, except where the existence of such liens, encumbrances or claims would not have a Material Adverse Effect.

(viii) The Offered Securities and all other outstanding shares of capital stock of the Company have been duly authorized and, when the Offered Securities have been delivered and paid for in accordance with this Agreement on each Closing Date (as defined below), such Offered Securities will have been validly issued, fully paid and nonassessable, will be consistent with the information in the General Disclosure Package and will conform in all material respects to the description thereof contained in the Prospectus; and the stockholders of the Company have no preemptive rights with respect to the Securities.

(ix) Except as disclosed in the General Disclosure Package, there are no contracts, agreements or understandings between the Company and any person that would give rise to a valid claim against the Company or any Underwriter for a brokerage commission, finder’s fee or other like payment in connection with this offering.

(x) No consent, approval, authorization, or order of, or filing with, any governmental agency or body or any court is required to be obtained or made by the Company for the consummation of the transactions contemplated by this Agreement in connection with the sale of the Offered Securities, except (i) such as have been obtained or will be obtained prior to the consummation of the offering and made under the Act, (ii) such as may be required under state securities laws, (iii) such as may be required under the rules and regulations of the National Association of Securities Dealers, Inc. (the “ NASD ”) and (iv) the filing of the Prospectus with the Commission.

(xi) Except as disclosed in the Prospectus, there are no contracts, agreements or understandings between the Company and any person granting such person the right to require the Company to file a registration statement under the Act with respect to any securities of the Company owned or to be owned by such person or to require the Company to include such securities in the securities registered pursuant to a Registration Statement or in any securities being registered pursuant to any other registration statement filed by the Company under the Act.

(xii) The execution, delivery and performance of this Agreement, and the consummation of the transactions herein contemplated will not result in a breach or violation of any of the terms and provisions of, or constitute a default under (assuming compliance with all applicable “Blue Sky” laws), (i) any statute, any rule, regulation or order of any governmental agency or body or any court, domestic or foreign, having jurisdiction over the Company or any subsidiary of the Company or any of their properties, (ii) any agreement or instrument to which the Company or any such subsidiary is a party or by which the Company or any such subsidiary is bound or to which any of the properties of the Company or any such subsidiary is subject, or (iii) the charter or by-laws of the Company or any such subsidiary (except, in the case of clauses (i) and (ii), where any such breach, violation or default would not, individually or in the aggregate, have a Material Adverse Effect).

(xiii) This Agreement has been duly authorized, executed and delivered by the Company.

(xiv) Except as disclosed in the General Disclosure Package, the Company and its subsidiaries have good and marketable title to all personal property and assets owned by them, in each case free from liens, encumbrances and defects that would materially affect the value thereof or materially interfere with the use made or to be made thereof by them; and except as disclosed in the General Disclosure Package, the Company and its subsidiaries hold any leased real or personal property under valid and enforceable leases with such exceptions as would not individually or in the aggregate have a Material Adverse Effect.

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(xv) Neither the Company or any of its subsidiaries own any real property.

(xvi) The Company and its subsidiaries possess adequate certificates, authorities or permits issued by appropriate governmental agencies or bodies necessary to conduct the business now operated by them and have not received any notice of proceedings relating to the revocation or modification of any such certificate, authority or permit that, if determined adversely to the Company or any of its subsidiaries, would individually or in the aggregate have a Material Adverse Effect.

(xvii) No labor dispute with the employees of the Company or any subsidiary exists or, to the knowledge of the Company, is imminent that would reasonably be expected to have a Material Adverse Effect.

(xviii) The Company and its subsidiaries own, possess or reasonably believe they can acquire on reasonable terms, adequate trademarks, trade names and other rights to inventions, know-how, patents, copyrights, confidential information and other intellectual property (collectively, “ intellectual property rights ”) necessary to conduct the business now operated by them, or presently employed by them (except such as will not individually or in the aggregate reasonably be expected to have a Material Adverse Effect), and have not received any notice of infringement of or conflict with asserted rights of others with respect to any intellectual property rights that, if determined adversely to the Company or any of its subsidiaries, would individually or in the aggregate have a Material Adverse Effect.

(xix) Except as disclosed in the General Disclosure Package, neither the Company nor any of its subsidiaries is in violation of any statute, any rule, regulation, decision or order of any governmental agency or body or any court, domestic or foreign, relating to the use, disposal or release of hazardous or toxic substances or relating to the protection or restoration of the environment or human exposure to hazardous or toxic substances (collectively, “ environmental laws ”), owns or operates any real property contaminated with any substance that is subject to any environmental laws, is liable for any off-site disposal or contamination pursuant to any environmental laws, or is subject to any claim relating to any environmental laws, which violation, contamination, liability or claim would individually or in the aggregate have a Material Adverse Effect; and the Company is not aware of any pending investigation which might lead to such a claim.

(xx) Except as disclosed in the General Disclosure Package, there are no pending actions, suits or proceedings against or affecting the Company, any of its subsidiaries or any of their respective properties that, if determined adversely to the Company or any of its subsidiaries, would individually or in the aggregate have a Material Adverse Effect, or would materially and adversely affect the ability of the Company to perform its obligations under this Agreement, or which are otherwise material in the context of the sale of the Offered Securities; and, to the Company’s knowledge, no such actions, suits or proceedings are threatened or contemplated.

(xxi) The financial statements included in each Registration Statement and the General Disclosure Package present fairly and in all material respects the financial position of the Company and its consolidated subsidiaries as of the dates shown and their results of operations and cash flows for the periods shown, and, except as otherwise disclosed in the Prospectus, such financial statements have been prepared in conformity with the generally accepted accounting principles in the United States applied on a consistent basis and the schedules included in each Registration Statement present fairly and in all material respects the information required to be stated therein and the assumptions used in preparing the pro forma financial statements included in each Registration Statement and the General Disclosure Package provide a reasonable basis for presenting the significant effects directly attributable to the transactions or events described therein, the related pro forma adjustments give appropriate effect to those assumptions, and the pro forma columns therein reflect the proper application of those adjustments to the corresponding historical financial statement amounts.

(xxii) Except as disclosed in the General Disclosure Package, since the date of the latest audited financial statements included in the General Disclosure Package there has been no material adverse change, nor any development or event involving a prospective material adverse change, in the condition (financial

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or other), business, properties or results of operations of the Company and its subsidiaries taken as a whole, and, except as disclosed in or contemplated by the General Disclosure Package, there has been no dividend or distribution of any kind declared, paid or made by the Company on any class of its capital stock.

(xxiii) Except as disclosed in the General Disclosure Package, the Company is not aware of (A) any material weaknesses in its internal control over financial reporting or (B) change in the Company’s internal control over financial reporting that has materially adversely affected, or is reasonably likely to materially adversely affect, the Company’s internal control over financial reporting;

(xxiv) Solely to the extent that the Sarbanes-Oxley Act has been applicable to the Company, there is and has been no failure on the part of the Company to comply in all material respects with any provision of the Sarbanes-Oxley Act of 2002 and the rules and regulations promulgated in connection therewith;

(xxv) The Company is not and, after giving effect to the offering and sale of the Offered Securities and the application of the proceeds thereof as described in the General Disclosure Package, will not be an “investment company” as defined in the Investment Company Act of 1940.

(xxvi) Neither the Company nor any of its affiliates does business with the government of Cuba or with any person or affiliate located in Cuba within the meaning of Section 517.075, Florida Statutes and the Company agrees to comply with such Section if prior to the completion of the distribution of the Offered Securities it commences doing such business.

(xxvii) Neither the Company nor any of its subsidiaries nor, to its knowledge, any director, officer, employee or other person associated with or acting on behalf of the Company or any of its subsidiaries has (A) used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expense relating to political activity, (B) made any direct or indirect unlawful payment to any foreign or domestic government official or employee from corporate funds, (C) caused the Company or any of its subsidiaries to be in violation of any provision of the U.S. Foreign Corrupt Practices Act of 1977 when such regulation becomes applicable to the Company or any of its subsidiaries, or (iv) made any bribe, rebate, payoff, influence payment, kickback or other unlawful payment;

(xxviii) The Company represents and warrants to the Underwriters that (A) the Registration Statement, the Prospectus, and, at the Applicable Time, any Statutory Prospectus and any Issuer Free Writing Prospectus comply, and any further amendments or supplements thereto will comply with any applicable laws or regulations of foreign jurisdictions in which the Prospectus, any Statutory Prospectus or any Issuer Free Writing Prospectus, as amended or supplemented, if applicable, are distributed in connection with the Directed Share Program, and that (B) no authorization, approval, consent, license, order, registration or qualification of or with any government, governmental instrumentality or court, other than such as have been obtained, is necessary under the securities law and regulations of foreign jurisdictions in which the Directed Shares are offered outside the United States.

(xxix) The Company has not offered, or caused the Underwriters to offer, any offered Securities to any person pursuant to the Directed Share Program with the specific intent to unlawfully influence (A) a customer or supplier of the Company to alter the customer’s or supplier’s level or type of business with the Company or (B) a trade journalist or publication to write or publish favorable information about the Company or its products.

(xxx) DIV Holding LLC owns one hundred percent (100%) of the issued and outstanding Securities.

3. Purchase, Sale and Delivery of Offered Securities . On the basis of the representations, warranties and agreements and subject to the terms and conditions set forth herein, the Company agrees to sell to each Underwriter, and each Underwriter agrees, severally and not jointly, to purchase from the Company, at a purchase

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price of $[    ] per share, the number of Firm Securities set forth below the caption “Company” and opposite the name of such Underwriter in Schedule A hereto.

The Company will deliver the Firm Securities to the Representatives for the accounts of the Underwriters, against payment of the purchase price in Federal (same day) funds by wire transfer to an account at a bank acceptable to Credit Suisse Securities (USA) LLC (“ Credit Suisse ”), at the office of Schulte Roth & Zabel LLP, 919 Third Avenue, New York, New York 10022, at 9:30 A.M., New York City time, on [                ], 2006, or at such other time not later than seven full business days thereafter as Credit Suisse and the Company determine, such time being herein referred to as the “ First Closing Date. ” For purposes of Rule 15c6-1 under the Securities Exchange Act of 1934, the First Closing Date (if later than the otherwise applicable settlement date) shall be the settlement date for payment of funds and delivery of securities for all the Offered Securities sold pursuant to the offering. The certificates for the Firm Securities so to be delivered will be in such denominations and registered in such names as Credit Suisse requests and will be made available for checking and packaging at the above office of Schulte Roth & Zabel LLP at least 24 hours prior to the First Closing Date.

In addition, upon written notice from Credit Suisse given to the Company from time to time not more than 30 days subsequent to the date of the Prospectus, the Underwriters may purchase all