FOURTH AMENDMENT TO FORMATION AND CONTRIBUTION AGREEMENT AND JOINT ESCROW INSTRUCTIONS

Exhibit 2.5

FOURTH AMENDMENT TO

FORMATION AND CONTRIBUTION AGREEMENT

AND JOINT ESCROW INSTRUCTIONS

THIS FOURTH AMENDMENT TO FORMATION AND CONTRIBUTION AGREEMENT AND JOINT ESCROW INSTRUCTIONS (this “ Amendment ”) is made and entered into as of March 28, 2008, by and among (i) NATIONWIDE HEALTH PROPERTIES, INC., a Maryland corporation (“ NHP ”), (ii) NHP/PMB L.P., a Delaware limited partnership (the “ Operating Partnership ”), (iii) PACIFIC MEDICAL BUILDINGS LLC, a California limited liability company (“ PMB LLC ”), (iv) PMB SPE SANTA CLARITA LLC, a California limited liability company (“ Clarita LLC ”), (v) PMB CHULA VISTA LLC, a California limited liability company (“ Vista LLC ”), (vi) LILIHA PARTNERS L.P., a California limited partnership (“ Liliha LP ”), (vii) ST. FRANCIS-LYNWOOD MEDICAL PLAZA L.P., a California limited partnership (“ Francis LP ”), (viii) EDEN MEDICAL PLAZA LP, a California limited partnership (“ Eden LP ”), (ix) PMB BURBANK #1 LLC, a California limited liability company (“ Burbank 1 LLC ”), (x) SAN GABRIEL VALLEY MEDICAL PLAZA LLC, a California limited liability company (“ SG Valley LLC ”), (xi) PMB GREEN VALLEY LLC, a Nevada limited liability company (“ Green LLC ”), (xii) THE PLAZA AT WASHOE, LLC, a Nevada limited liability company (“ Washoe LLC ”), (xiii) THE TERRACE AT SOUTH MEADOWS, LLC, a Nevada limited liability company (“ Terrace LLC ”), (xiv) PMB HILLSBORO LLC, an Oregon limited liability company (“ Hillsboro LLC ”), (xv) PMB TORRANCE 1 LLC, a California limited liability company (“ Torrance LLC ”), (xvi) PMB BURBANK #2 LLC, a California limited liability company (“ Burbank 2 LLC ”), (xvii) PDP ORANGE LLC, a Delaware limited liability company (“ Orange LLC ”), (xviii) PDP MISSION VIEJO LLC, a Delaware limited liability company (“ Mission LLC ”), (xix) PDP POMERADO LLC, a California limited liability company (“ Pomerado LLC ”), (xx) PMB PASADENA LLC, a California limited liability company (“ Pasadena LLC ”), and (xxi) PMB GILBERT LLC, a Delaware limited liability company (“ Gilbert LLC ” and, together with Clarita LLC, Vista LLC, Liliha LP, Francis LP, Eden LP, Burbank 1 LLC, SG Valley LLC, Green LLC, Washoe LLC, Terrace LLC, Hillsboro LLC, Torrance LLC, Burbank 2 LLC, Orange LLC, Mission LLC, Pomerado LLC and Pasadena LLC, the “ Transferors ”).

R E C I T A L S

A. NHP, PMB LLC and the Transferors entered into that certain Formation and Contribution Agreement and Joint Escrow Instructions, dated as of February 25, 2008 (the “ Original Contribution Agreement ”), as amended by that certain First Amendment to Formation and Contribution Agreement and Joint Escrow Instructions, dated as of March 10, 2008 (the “ First Amendment ”), as further amended by that certain Letter Agreement Re: Due Diligence Waiver Letter and Second Amendment to that certain Formation and Contribution Agreement and Joint Escrow Instructions, dated as of March 14, 2008 (the “ Second Amendment ”), and as further amended by that certain Third Amendment to Formation and Contribution Agreement and Joint Escrow Instructions, dated as of March 26, 2008 (the “ Third Amendment ,” together with the First Amendment, Second Amendment and Original Contribution Agreement, the “ Contribution Agreement ”). All

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capitalized terms used but not otherwise defined herein shall have the meanings set forth for the same in the Contribution Agreement.

B. NHP, the Operating Partnership, PMB LLC and the Transferors desire to amend the Contribution Agreement in accordance with the terms and conditions set forth herein.

A G R E E M E N T

NOW, THEREFORE, in consideration of the mutual covenants contained in this Amendment and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, NHP, the Operating Partnership, PMB LLC and the Transferors hereby agree as follows:

1.1 Whole OP Unit Requirements .

1.1.1 Delivery of OP Units . The Contribution Agreement is hereby amended by deleting the first sentence of Section 2.3(b) thereof in its entirety and inserting the following in lieu thereof:

“At the applicable Closing of each Contribution Transaction, Transferee shall cause (i) to be issued to each of the OP Unit Recipients for such Property, if any, OP Units equal in value (as determined in accordance with this Section 2.3(b)) to the OP Unit Portion attributable to the Allocable Share of such OP Unit Recipient, as identified in the Notice for such Property (provided, however, that Transferee shall not issue any fractional OP Units, and the number of OP Units to be issued pursuant to the foregoing calculation shall be rounded to the nearest whole number to the extent required to avoid such a result), and (ii) to be paid to each of the Cash Recipients for such Property, if any, the Cash Portion attributable to the Allocable Share of such Cash Recipient in cash by wire transfer of federal funds, as identified in the Notice for such Property.”

1.1.2 Pledge of OP Units . The Contribution Agreement is hereby amended by adding the following sentence after the first sentence of Section 6.1.21 thereof:

“ Notwithstanding anything to the contrary contained herein, the OP Unit Recipients shall not pledge any fractional OP Units, and the number of OP Units to be pledged pursuant to the foregoing calculation shall be rounded to the nearest whole number to the extent required to avoid such a result.”

1.1.3 Sharp Rees-Stealy Pledge of OP Units . The Contribution Agreement is hereby amended by adding the following sentence after the fourth sentence of Section 10.5 thereof:

“ Notwithstanding anything to the contrary contained herein, the holders of the Sharp Rees-Stealy Pledged Units shall not pledge any fractional OP Units, and the

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number of OP Units to be pledged pursuant to the foregoing calculation shall be rounded to the nearest whole number to the extent required to avoid such a result.”

1.2 Existing Property Closing Date . The Contribution Agreement is hereby amended by deleting the first sentence of Section 7.1.1 thereof in its entirety and inserting the following in lieu thereof:

“Subject to the provisions of this Agreement, the Closing with respect to all of the Existing Properties shall take place concurrently on April 1, 2008 or such other date as the parties hereto may agree; provided, however, that (a) the Closing of the Contribution Transaction relating to the Properties leased by Green LLC, Terrace LLC and Hillsboro LLC shall take place on May 1, 2008, (b) the Closing of the Contribution Transaction relating to the Property leased by Liliha LP shall take place on June 1, 2008, and (c) the Closing of the Contribution Transaction relating to the Property owned by Vista LLC shall take place on November 1, 2008. Notwithstanding anything to the contrary contained in Sections 7.1.3, 7.5.1 and 16.18 hereof, to the extent that any of the dates specified in the preceding sentence fall on a Saturday, Sunday or legal holiday, the Closing shall take place on the next Business Day, provided that, for purposes of any and all adjustments and prorations hereunder, the Closing Date shall be deemed to have occurred on the dates specified in the preceding sentence.”

1.3 Cap Rate Adjustments . The Contribution Agreement is hereby amended by deleting Exhibit “B-2” attached thereto in its entirety and inserting Exhibit “B-2” attached hereto in lieu thereof.

1.4 Sample Cap Rate Adjustment Calculation . The Contribution Agreement is hereby amended by deleting Exhibit “B-3” attached thereto in its entirety and inserting Exhibit “B-3” attached hereto in lieu thereof.

2.1 Governing Law . This Amendment and the legal relations between the parties hereto shall be governed by and construed and enforced in accordance with the laws of the State of California, without regard to its principles of conflicts of law.

2.2 Counterparts . This Amendment may be executed in as many counterparts as may be deemed necessary and convenient, and by the different parties hereto on separate counterparts, each of which, when so executed, shall be deemed an original, but all such counterparts shall constitute one and the same instrument.

2.3 Headings . The Section headings of this Amendment are for convenience of reference only and shall not be deemed to modify, explain, restrict, alter or affect the meaning or interpretation of any provision hereof.

2.4 Construction . This Amendment shall not be construed more strictly against one party hereto than against any other party hereto merely by virtue of the fact that it may have been prepared by counsel for one of the parties.

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2.5 Effect of Amendment . In the event of any inconsistency between the terms of the Contribution Agreement and the terms of this Amendment, the terms of this Amendment shall prevail.

2.6 Ratification . Except as otherwise