GUARANTY

Exhibit 10.13

GUARANTY

dated as of March 26, 2008

among

SBARRO HOLDINGS, LLC,

and

THE SUBSIDIARY GUARANTORS FROM TIME TO TIME PARTY HERETO,

and

NATIXIS, NEW YORK BRANCH,

as Administrative Agent

TABLE OF CONTENTS

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GUARANTY dated as of March 26, 2008 (as amended, restated, modified or supplemented from time to time, this “ Agreement ”) among SBARRO HOLDINGS, LLC, a Delaware limited liability company (“ Holdings ”), the Subsidiary Guarantors from time to time party hereto (the “ Subsidiary Guarantors ” and, together with Holdings, the “ Guarantors ”) and Natixis, New York Branch, as Administrative Agent for the benefit of the Credit Parties referred to herein.

Holdings and Sbarro, Inc., a New York corporation (the “ Borrower ”), propose to enter into a second lien credit agreement dated as of March 26, 2009 (as amended, restated, modified, supplemented, restructured or refinanced from time to time, the “ Credit Agreement ”) among Holdings, the Borrower, the banks and other lending institutions from time to time party thereto (each a “ Lender ” and, collectively, the “ Lenders ”), and Natixis, New York Branch, as Administrative Agent and Collateral Agent. Capitalized terms used but not defined herein shall have the meanings assigned thereto in the Credit Agreement.

The Lenders, the Administrative Agent and the Collateral Agent and their respective successors and assigns, are herein referred to individually as a “ Credit Party ” and collectively as the “ Credit Parties ”.

To induce the Credit Parties to enter into the Credit Agreement and the other Loan Documents referred to therein (collectively with the Credit Agreement, the “ Loan Documents ”), and as a condition precedent to the obligations of the Credit Parties under the Credit Agreement, Holdings and each of the Subsidiaries of the Borrower which shall become parties hereto from time to time in accordance with Section 5.11 (each a “ Subsidiary Guarantor ” and, collectively, the “ Subsidiary Guarantors ” and, together with Holdings, the “ Guarantors ”), have agreed, jointly and severally, to provide a guaranty of all obligations of Holdings, the Borrower and the other Loan Parties under and in respect of the Loan Documents. Holdings, the Borrower and the Subsidiary Guarantors are referred to herein individually as a “ Loan Party ” and, collectively, as the “ Loan Parties ”). As used herein, “ Other Loan Parties ” means, with respect to any Guarantor, any and all of the Loan Parties other than such Guarantor.

Holdings, and the Subsidiary Guarantors will receive not insubstantial benefits from the financial accommodation to be provided by the Credit Parties under the Loan Documents. Accordingly, the Guarantors hereby agree with the Administrative Agent for the benefit of the Credit Parties as follows:

ARTICLE I

GUARANTY

Section 1.01 The Guaranty . Each Guarantor unconditionally guarantees, jointly with the other Guarantors, and severally, as a primary obligor and not merely as a surety: (x) the due and punctual payment of all Second Lien Credit Obligations of the Borrower whether now or hereafter due, owing or incurred in any manner, whether actual or contingent, whether incurred solely or jointly with any other Person and whether as principal or surety (and including all liabilities in connection with any notes, bills or other instruments accepted by any Credit Party in connection therewith), together in each case with all renewals, modifications, consolidations or extensions thereof, and (y) the due and punctual performance of all covenants, agreements,

obligations and liabilities of Holdings, the Borrower and the Other Loan Parties under or pursuant to the Loan Documents (all such monetary and other obligations being herein collectively referred to as the “ Guaranteed Obligations ”).

Anything contained in this Agreement to the contrary notwithstanding, the obligations of each Subsidiary Guarantor hereunder shall be limited to a maximum aggregate amount equal to the greatest amount that would not render such Subsidiary Guarantor’s obligations hereunder subject to avoidance as a fraudulent transfer or conveyance under Section 548 of Title 11 of the United States Code or any provisions of applicable state law (collectively, the “ Fraudulent Transfer Laws ”), in each case after giving effect to all other liabilities of such Subsidiary Guarantor, contingent or otherwise, that are relevant under the Fraudulent Transfer Laws (specifically excluding, however, any liabilities of such Subsidiary Guarantor (i) in respect of intercompany indebtedness to the Borrower or any of its Affiliates to the extent that such indebtedness (A) would be discharged or would be subject to a right of set-off in an amount equal to the amount paid by such Subsidiary Guarantor hereunder or (B) has been pledged to, and is enforceable by, the Collateral Agent on behalf of the Credit Parties and (ii) under any guaranty of Indebtedness subordinated in right of payment to the Guaranteed Obligations which guaranty contains a limitation as to a maximum amount similar to that set forth in this paragraph pursuant to which the liability of such Subsidiary Guarantor hereunder is included in the liabilities taken into account in determining such maximum amount) and after giving effect as assets of such Subsidiary Guarantor to the value (as determined under the applicable provisions of the Fraudulent Transfer Laws) of any rights to subrogation, contribution, reimbursement, indemnity or similar rights of such Subsidiary Guarantor pursuant to (i) applicable Law or (ii) any agreement providing for an equitable allocation among such Subsidiary Guarantor and other Affiliates of the Borrower of obligations arising under guaranties by such parties (including the agreements in Article II of this Agreement). If any Subsidiary Guarantor’s liability hereunder is limited pursuant to this paragraph to an amount that is less than the total amount of the Guaranteed Obligations, then it is understood and agreed that the portion of the Guaranteed Obligations for which such Subsidiary Guarantor is liable hereunder shall be the last portion of the Guaranteed Obligations to be repaid.

Section 1.02 Guaranty Absolute . Each Guarantor guarantees that the Guaranteed Obligations will be paid strictly in accordance with the terms of the Loan Documents, including the Intercreditor Agreement, regardless of any Law now or hereafter in effect in any jurisdiction affecting any of such terms or the rights of the Credit Parties with respect thereto. The obligations of the Guarantors under this Agreement are independent of the Guaranteed Obligations, and a separate action or actions may be brought and prosecuted against each Guarantor to enforce this Agreement, irrespective of whether any action is brought against the Borrower or any Other Loan Party or whether the Borrower or any Other Loan Party is joined in any such action or actions. This Agreement is an absolute and unconditional guaranty of payment when due, and not of collection, by each Guarantor, jointly and severally with each other Guarantor of the Guaranteed Obligations in each and every particular. The obligations of each Guarantor hereunder are several from those of the Other Loan Parties and are primary obligations concerning which each Guarantor is the principal obligor. The Credit Parties shall not be required to mitigate damages or take any action to reduce, collect or enforce the Guaranteed Obligations.

The obligations of each Guarantor hereunder shall not be subject to any reduction, limitation, impairment or termination for any reason, including the existence of any claim, set-off

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or other right which any Guarantor may have at any time against any Other Loan Party, any Agent or other Credit Party or any other Person, whether in connection herewith or any unrelated transactions. Without limiting the generality of the foregoing, each Guarantor’s liability shall extend to all amounts that constitute part of the Guaranteed Obligations and would be owed by any Other Loan Party to any Credit Party under the Loan Documents but for the fact that they are unenforceable or not allowable due to the existence of a bankruptcy, reorganization or similar proceeding involving the Borrower or such Other Loan Party.

Without limiting the generality of the foregoing, the obligations of each Guarantor hereunder shall not be released, discharged or otherwise affected or impaired by:

(i) any extension, renewal, settlement, compromise, acceleration, waiver or release in respect of any obligation of any Other Loan Party under the Credit Agreement, the Notes, any other Loan Document or any other agreement or instrument evidencing or securing any Guaranteed Obligation, by operation of Law or otherwise;

(ii) any change in the manner, place, time or terms of payment of any Guaranteed Obligation or any other amendment, supplement or modification to the Credit Agreement, the Notes, any other Loan Document or any other agreement or instrument evidencing or securing any Guaranteed Obligation;

(iii) any release, non-perfection or invalidity of any direct or indirect security for any Guaranteed Obligation, any sale, exchange, surrender, realization upon, offset against or other action in respect of any direct or indirect security for any Guaranteed Obligation or any release of any Other Loan Party or any other guarantor or guarantors of any Guaranteed Obligation;

(iv) any change in the existence, structure or ownership of any Other Loan Party or any insolvency, bankruptcy, reorganization, arrangement, readjustment, composition, liquidation or other similar proceeding affecting any Other Loan Party or its assets or any resulting disallowance, release or discharge of all or any portion of any Guaranteed Obligation;

(v) the existence of any claim, set-off or other right which any Guarantor may have at any time against any Other Loan Party, any Agent, any other Credit Party or any other Person, whether in connection herewith or any unrelated transaction; provided that nothing herein shall prevent the assertion of any such claim by separate suit or compulsory counterclaim;

(vi) any invalidity or unenforceability relating to or against any Other Loan Party for any reason of the Credit Agreement, any Note, any other Loan Document or any other agreement or instrument evidencing or securing any Guaranteed Obligation or any provision of applicable Law purporting to prohibit the payment by any Other Loan Party of any Guaranteed Obligation;

(vii) any failure by any Agent or any other Credit Party: (A) to file or enforce a claim against any Other Loan Party or its estate (in a bankruptcy or other proceeding); (B) to give notice of the existence, creation or incurrence by any Other Loan

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Party of any new or additional indebtedness or obligation under or with respect to the Guaranteed Obligations; (C) to commence any action against any Other Loan Party; (D) to disclose to any Guarantor any facts which such Agent or such other Credit Party may now or hereafter know with regard to any Other Loan Party; or (E) to proceed with due diligence in the collection, protection or realization upon any collateral securing the Guaranteed Obligations;

(viii) any direction as to application of payment by any other Loan Party or any other Person;

(ix) any subordination by any Credit Party of the payment of any Guaranteed Obligation to the payment of any other liability (whether matured or unmatured) of any Other Loan Party to its creditors;

(x) any act or failure to act by the Administrative Agent, any other Credit Party under this Agreement or otherwise which may deprive any Guarantor of any right to subrogation, contribution or reimbursement against any Other Loan Party or any right to recover full indemnity for any payments made by such Guarantor in respect of the Guaranteed Obligations; or

(xi) any other act or omission to act or delay of any kind any Other Loan Party, the Administrative Agent or any Credit Party or any other Person or any other circumstance whatsoever which might, but for the provisions of this clause, constitute a legal or equitable discharge of any Guarantor’s obligations hereunder (except that a Guarantor may assert the defense of final payment in full of the Guaranteed Obligations).

Each Guarantor irrevocably and unconditionally has delivered this Agreement to the Administrative Agent for the benefit of the Credit Parties, and the failure by any Other Loan Party or any other Person to sign this Agreement or a guaranty similar to this Agreement or otherwise shall not discharge the obligations of any Guarantor hereunder. The irrevocable and unconditional liability of each Guarantor hereunder applies whether it is jointly and severally liable for the entire amount of the Guaranteed Obligations, or only for a pro-rata portion, and without regard to any rights (or the impairment thereof) of subrogation, contribution or reimbursement that such Guarantor may now or hereafter have against any Other Loan Party or any other Person. This Agreement is and shall remain fully enforceable against each Guarantor irrespective of any defenses that any Other Loan Party may have or assert in respect of the Guaranteed Obligations, including, without limitation, failure of consideration, breach of warranty, payment, statute of frauds, statute of limitations, accord and satisfaction and usury, except that a Guarantor may assert the defense of final payment in full of the Guaranteed Obligations.

Section 1.03 Payments .

(a) Payments to be Made Upon Default . If the Borrower or any Other Loan Party fails to pay or perform any Guaranteed Obligation when due in accordance with its terms (whether at stated maturity, by acceleration or otherwise) or if any Event of Default specified in Section 8.01(f ) of the Credit Agreement occurs with respect to the Borrower, the Guarantors shall, in accordance with the terms of the Intercreditor Agreement and forthwith on demand of the Administrative Agent, pay the aggregate amount of all Guaranteed Obligations owed respectively to the Administrative Agent.

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(b) General Provisions as to Payments . Each payment hereunder shall be made without set-off, counterclaim or other deduction, in Federal or other funds immediately available in New York City, to the Administrative Agent at the addresses referred to in Section 5.01 (it being understood that a Guarantor may assert the defense of final payment in full of the Guaranteed Obligations).

(c) Application of Payments . All payments received by the Administrative Agent hereunder shall be applied as provided in Section 8.03 of the Credit Agreement.

Section 1.04 Discharge; Reinstatement in Certain Circumstances . Each Guarantor’s obligations hereunder shall remain in full force and effect until (i) the principal of and interest (including interest accruing on or after the commencement of Insolvency or Liquidation Proceeding, whether or not a claim for such interest is, or would be, allowed in such Insolvency or Liquidation Proceeding) and premium, if any, on all Indebtedness outstanding under the Loan Documents and termination of all commitments to lend or otherwise extend credit under the Loan Documents, (ii) payment in full of all other Second Lien Credit Obligations that are due and payable or otherwise accrued and owing at or prior to the time such principal and interest are paid (including legal fees and other expenses, costs or charges accruing on or after the commencement of any Insolvency or Liquidation Proceeding, whether or not a claim for such fees, expenses, costs or charges is, or would be, allowed in such Insolvency or Liquidation Proceeding but excluding contingent indemnification obligations), (the occurrence of all of the foregoing subclauses (i) and (ii) being referred to herein as “ Discharge of Second Lien Credit Obligations ”) and (iii) such time as such Guarantor is no longer required to be a Guarantor under the Credit Agreement. No payment or payments made by the Borrower, any Other Loan Party or any other Person or received or collected by any Credit Party from the Borrower, any Other Loan Party or any other Person by virtue of any action or proceeding or any set-off or appropriation or application at any time or from time to time in reduction of or in payment of the Guaranteed Obligations shall be deemed to modify, reduce, release or otherwise affect the liability of any Guarantor hereunder, it being understood that each Guarantor shall, notwithstanding any such payment or payments, remain liable for the Guaranteed Obligations until Discharge of Second Lien Credit Obligations. If at any time any payment by the Borrower, any Other Loan Party or any other Person of any Guaranteed Obligation is rescinded or must otherwise be restored or returned upon the insolvency, bankruptcy, dissolution, liquidation or reorganization of the Borrower or such Other Loan Party or other Person or upon or as a result of the appointment of a receiver, intervener or conservator of, or trustee or similar officer for, the Borrower or such Other Loan Party or other Person or any substantial part of its respective property or otherwise, each Guarantor’s obligations hereunder with respect to such payment shall be reinstated as though such payment had been due but not made at such time. Each Guarantor agrees that payment or performance of any of the Guaranteed Obligations or other acts which toll any statute of limitations applicable to the Guaranteed Obligations shall also toll the statute of limitations applicable to each Guarantor’s liability hereunder.

Section 1.05 Waiver by the Guarantors . Each Guarantor hereby waives, only to the extent permitted by applicable Law, presentment to, demand of payment from and

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protest to the Other Loan Parties of any of the Guaranteed Obligations, and also waives to the extent permitted by applicable Law, promptness, diligence, notice of acceptance of its guarantee, any other notice with respect to any of the Guaranteed Obligations and this Agreement and any requirement that any Agent or any other Credit Party protect, secure, perfect or insure any Lien or any property subject thereto. Each Guarantor further waives to the extent permitted by applicable Law, any right to require that resort be had by any Agent or any other Credit Party to any security held for payment of the Guaranteed Obligations or to any balance of any deposit, account or credit on the books of any Agent or any other Credit Party in favor of any Loan Party or any other Person. Each Guarantor hereby consents and agrees to each of the following to the fullest extent permitted by Law, and agrees that such Guarantor’s obligations under this Agreement shall not be released, diminished, impaired, reduced or adversely affected by any of the following, and waives to the extent permitted by applicable Law, any rights (including rights to notice) which such Guarantor might otherwise have as a result of or in connection with any of the following:

(i) any renewal, extension, modification, increase, decrease, alteration or rearrangement of all or any part of the Guaranteed Obligations or any instrument executed in connection therewith, or any contract or understanding with any Other Loan Party, any Agent, the other Credit Parties, or any of them, or any other Person, pertaining to the Guaranteed Obligations;

(ii) any adjustment, indulgence, forbearance or compromise that might be granted or given by any Agent or any other Credit Party to any Other Loan Party or any other Person liable on the Guaranteed Obligations; or the failure of any Agent or any other Credit Party to assert any claim or demand or to exercise any right or remedy against any Other Loan Party under the provisions of any Loan Document or otherwise; or any rescission, waiver, amendment or modification of, or any release from any of the terms or provisions of, any Loan Document or any other agreement, including with respect to any Other Loan Party under this Agreement;

(iii) the insolvency, bankruptcy, arrangement, adjustment, composition, liquidation, disability, dissolution or lack of power of any Other Loan Party or any other Person at any time liable for the payment of all or part of the Guaranteed Obligations; or any dissolution of any Other Loan Party, or any change, restructuring or termination of the corporate structure or existence of any Other Loan Party, or any sale, lease or transfer of any or all of the assets of any Other Loan Party, or any change in the shareholders, partners, or members of any Other Loan Party; or any default, failure or delay, willful or otherwise, in the performance of the Guaranteed Obligations;

(iv) the invalidity, illegality or unenforceability of all or any part of the Guaranteed Obligations, or any document or agreement executed in connection with the Guaranteed Obligations, for any reason whatsoever, including the fact that the Guaranteed Obligations, or any part thereof, exceed the amount permitted by Law, the act of creating the Guaranteed Obligations or any part thereof is ultra vires , the officers or representatives executing the documents or otherwise creating the Guaranteed Obligations acted in excess of their authority, the Guaranteed Obligations violate applicable usury Laws, any Other Loan Party has valid defenses, claims or offsets (whether at Law, in equity

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or by agreement) which render the Guaranteed Obligations wholly or partially uncollectible from such Other Loan Party, the creation, performance or repayment of the Guaranteed Obligations (or the execution, delivery and performance of any document or instrument representing part of the Guaranteed Obligations or executed in connection with the Guaranteed Obligations or given to secure the repayment of the Guaranteed Obligations) is illegal, uncollectible, legally impossible or unenforceable, or the documents or instruments pertaining to the Guaranteed Obligations have been forged or otherwise are irregular or not genuine or authentic;

(v) any full or partial release of the liability of any Other Loan Party or of any other Person now or hereafter liable, whether directly or indirectly, jointly, severally, or jointly and severally, to pay, perform, guarantee or assure the payment of the Guaranteed Obligations or any part thereof, it being recognized, acknowledged and agreed by each Guarantor that such Guarantor may be required to pay the Guaranteed Obligations in full without assistance or support of any other Person, and such Guarantor has not been induced to enter into this Agreement on the basis of a contemplation, belief, understanding or agreement that any party other than the Borrower will be liable to perform the Guaranteed Obligations, or that the Credit Parties will look to any other party to perform the Guaranteed Obligations;

(vi) the taking or accepting of any other security, collateral or guarantee, or other assurance of payment, for all or any part of the Guaranteed Obligations;

(vii) any release, surrender, exchange, subordination, deterioration, waste, loss or impairment (including negligent, willful, unreasonable or unjustifiable impairment) of any collateral, property or security, at any time existing in connection with, or assuring or securing payment of, all or any part of the Guaranteed Obligations;

(viii) any right that any Guarantor may now or hereafter have under Section 3-606 of the UCC or otherwise to unimpaired collateral;

(ix) the failure of any Agent, any other Credit Party or any other Person to exercise diligence or reasonable care in the preservation, protection, enforcement, sale or other handling or treatment of all or any part of such collateral, property or security;

(x) the fact that any collateral, security, security interest or lien contemplated or intended to be given, created or granted as security for the repayment of the Guaranteed Obligations shall not be properly perfected or created, or shall prove to be unenforceable or subordinate to any other security interest or lien, it being recognized and agreed by each Guarantor that such Guarantor is not entering into this Agreement in reliance on, or in contemplation of the benefits of, the validity, enforceability, collectibility or value of any of the Collateral;

(xi) any payment by any Other Loan Party to the Administrative Agent, any other Agent or any other Credit Party being held to constitute a preference under Title 11 of the United States Code or any similar Federal, foreign or state Law, or for any reason any Agent or any other Credit Party being required to refund such payment or pay such amount to any Other Loan Party or someone else;

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(xii) any other action taken or omitted to be taken with respect to the Guaranteed Obligations, or the security and collateral therefor, whether or not such action or omission prejudices any Guarantor or increases the likelihood that any Guarantor will be required to pay the Guaranteed Obligations pursuant to the terms hereof, it being the unambiguous and unequivocal intention of each Guarantor that such Guarantor shall be obligated to pay the Guaranteed Obligations when due, subject to the terms of the Intercreditor Agreement, notwithstanding any occurrence, circumstance, event, action or omission whatsoever, whether or not contemplated, and whether or not otherwise or particularly described herein, except for the full payment and satisfaction of the Guaranteed Obligations in cash;

(xiii) the fact that all or any of the Guaranteed Obligations cease to exist by operation of Law, including by way of a discharge, limitation or tolling thereof under applicable bankruptcy Laws;

(xiv) the existence of any claim, set-off or other right which any Guarantor may have at any time against any Other Loan Party, the Administrative Agent, any other Credit Party or any other Person, whether in connection herewith or any unrelated transactions; provided that nothing herein shall prevent the assertion of any such claim by separate suit or compulsory counterclaim; and

(xv) any other circumstance that might in any manner or to any extent otherwise constitute a defense available to, vary the risk of, or operate as a discharge of, such Guarantor as a matter of Law or equity (it being understood that a Guarantor may assert the defense of final payment in full of the Guaranteed Obligations).

All waivers herein contained shall be without prejudice to the right of the Administrative Agent at its option to proceed against any Loan Party or any other Person, whether by separate action or by joinder.

Section 1.06 Agreement to Pay; Subordination of Subrogation Claims . In furtherance of the foregoing and not in limitation of any other right that the Administrative Agent, any other Agent or any other Credit Party has at Law or in equity against any Guarantor by virtue hereof, upon the failure of any Other Loan Party to pay any Guaranteed Obligation when and as the same shall become due, whether at maturity, by acceleration, after notice of prepayment or otherwise, subject to the terms of the Intercreditor Agreement, each Guarantor hereby promises to and will forthwith pay, or cause to be paid, to the Administrative Agent, such other Credit Party as designated thereby in cash the amount of such unpaid Guaranteed Obligations. Upon payment by any Guarantor of any sums to the Administrative Agent or any Credit Party as provided above, all rights of such Guarantor against any Other Loan Party arising as a result thereof by way of right of subrogation, contribution, reimbursement, indemnity or otherwise shall (including, without limitation, in the case of any Guarantor, any rights of such Guarantor arising under Article II of this Agreement) in all respects be subordin