Press Release

For Immediate News Release

July 13, 2011

MISSION WEST PROPERTIES ANNOUNCES SECOND QUARTER 2011 OPERATING RESULTSCupertino, CA – Mission West Properties, Inc. (NASDAQ: MSW) reported today that Funds From Operations (“FFO”) for the quarter ended June 30, 2011, was approximately $13,708,000, or $0.13 per diluted common share, (considering the potential effect of all O.P. units being exchanged for shares of the Company’s common stock) as compared to approximately

$16,559,000, or $0.16 per diluted common share, for the same period in 2010. Realized gain from investment in marketable securities accounted for approximately $2,215,000, or $0.02 per diluted common share, and litigation proceeds accounted for

approximately $903,000, or $0.01 per diluted common share, for the quarter ended June 30, 2010. On a sequential quarter basis, FFO for the quarter ended March 31, 2011, was approximately $0.15 per diluted common share. For the six months ended June 30, 2011, FFO decreased to $29,950,000, or $0.28 per diluted common share, from FFO of $33,066,000, or $0.31 per diluted common share, for the six months ended June 30, 2010. Realized and unrealized gain from investment in

marketable securities and litigation proceeds accounted for approximately $0.05 per diluted common share for the six months ended June 30, 2010.

Net income for the quarter ended June 30, 2011, was approximately $7,370,000 as compared to approximately $10,041,000 for the quarter ended June 30, 2010. Net income per diluted share available to common stockholders was approximately $0.08 for the quarter ended June 30, 2011 compared to $0.11 for the quarter ended June 30, 2010, a per share decrease of approximately 27%. Net income for the six months ended June 30, 2011, was approximately $17,305,000 as compared to approximately $20,185,000 for the six months ended June 30, 2010. For the six months ended June 30, 2011, net income per diluted share available to common stockholders was $0.19, down from $0.22 a year ago, a per share decrease of approximately

14%. Realized and unrealized gain from investment in marketable securities and litigation proceeds accounted for approximately

$0.05 per diluted common share for the six months ended June 30, 2010.

Company Profile

Mission West Properties, Inc. operates as a self-managed, self-administered and fully integrated REIT engaged in the management, leasing, marketing, development and acquisition of commercial R&D properties, primarily located in the Silicon Valley portion of the San Francisco Bay Area. Currently, the Company manages 111 properties totaling approximately 8.0 million rentable square feet. For additional information, please contact Investor Relations at 408-725-0700.

The matters described herein contain forward-looking statements. Such statements can be identified by the use of forward- looking terminology such as “will,” “anticipate,” “estimate,” “expect,” “intend,” or similar words. Forward-looking statements involve a number of risks, uncertainties or other factors beyond the Company’s control, which may cause material differences in actual results, performance or other expectations. These factors include, but are not limited to, the ability to complete acquisitions from the Berg Group and other factors detailed in the Company’s registration statements, and periodic filings with the Securities & Exchange Commission.

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MISSION WEST PROPERTIES, INC.SELECTED FINANCIAL DATA

(In thousands, except share, per share and property data amounts)

STATEMENTS OF OPERATIONSOPERATING REVENUES:Three MonthsEnded

Jun 30, 2011

Three MonthsEnded

Jun 30, 2010

Six MonthsEnded

Jun 30, 2011

Six MonthsEnded

Jun 30, 2010

Rental income $20,295 $20,659 $42,072 (6) $41,462

Tenant reimbursements 4,045 4,028 8,690 8,453

Other income 462 1,204 1,562 1,862

Total operating revenues 24,802 25,891 52,324 51,777

OPERATING EXPENSES:

Operating and maintenance 2,595 3,061 5,250 5,972

Real estate taxes 3,150 3,388 6,354 6,571

General and administrative 522 563 1,043 1,081

Depreciation and amortization 5,844 (1) 5,976 (1) 11,671 (1) 11,816 (1)

Total operating expenses 12,111 12,988 24,318 25,440

Operating income 12,691 12,903 28,006 26,337

OTHER INCOME (EXPENSES):

Equity in earnings of unconsolidated joint venture

27

147

18

224

Interest and dividend income

57

-

126

50

Realized and unrealized gain from investment

-

2,215

-

4,067

Interest expense

(5,246)

(4,778)

(10,525)

(9,627)

Interest expense – related parties

(144)

(327)

(291)

(624)

Income from continuing operations

7,385

10,160

17,334

20,427

Discontinued operations:

Loss from discontinued operations (15) (119) (29) (242)

Net income

7,370

10,041

17,305

20,185

Net income attributable to noncontrolling interests

(5,491)

(7,581)

(13,027)

(15,267)

Net income available to common stockholders

$1,879

$2,460

$4,278

$4,918

Income per share from continuing operations: Basic

$0.08

$0.11

$0.19

$0.23

Diluted

$0.08

$0.11

$0.19

$0.22

Income per share from discontinued operations:

Basic - - - - Diluted - - - -

Net income per share to common stockholders:

Basic

$0.08

$0.11

$0.19

$0.22

Diluted

$0.08

$0.11

$0.19

$0.22

Weighted average shares of common stock (basic)

22,495,605

21,957,654

22,392,427

21,919,632

Weighted average shares of common stock (diluted)

22,756,006

22,123,527

22,583,358

22,090,313

Weighted average O.P. units outstanding

82,790,430

83,326,965

82,893,608

83,362,225

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FUNDS FROM OPERATIONSThree MonthsEnded

Jun 30, 2011

Three MonthsEnded

Jun 30, 2010

Six MonthsEnded

Jun 30, 2011

Six MonthsEnded

Jun 30, 2010

Funds from operations $13,708 $16,559 $29,950 $33,066

Funds from operations per share (2) $0.13 $0.16 $0.28 $0.31

Outstanding common stock 22,584,770 21,959,070 22,584,770 21,959,070

Outstanding O.P. units 82,701,265 83,326,965 82,701,265 83,326,965

Weighted average O.P. units and common stock

outstanding (diluted) 105,546,436 105,450,492 105,476,966 105,452,538

FUNDS FROM OPERATIONS CALCULATIONThree MonthsEnded

Jun 30, 2011

Three MonthsEnded

Jun 30, 2010

Six MonthsEnded

Jun 30, 2011

Six MonthsEnded

Jun 30, 2010

Net income $7,370 $10,041 $17,305 $20,185

Add:

Depreciation and amortization 6,384 6,556 12,736 12,963

Depreciation and amortization in

unconsolidated joint venture 60 60 119 119

Less:

Noncontrolling interests in joint ventures

(106)

(98)

(210)

(201)

Funds from operations

$13,708

$16,559

$29,950

$33,066

Funds From Operations (“FFO”) is a non-GAAP financial measurement used by real estate investment trusts (“REITs”) to measure and compare operating performance. As defined by NAREIT, FFO represents net income (loss) (computed in accordance with GAAP, accounting principles generally accepted in the United States of America), excluding gains (or losses) from debt restructuring and sales of property, plus real estate related depreciation and amortization (excluding amortization of deferred financing costs and depreciation of non-real estate assets) and after adjustments for unconsolidated partnerships and joint ventures. Management considers FFO to be an appropriate supplemental measure of the Company’s operating and financial performance because when compared year over year, it reflects the impact to operations from trends in occupancy rates, rental rates, operating costs, general and administrative expenses and interest costs, providing a perspective not immediately apparent from net income. In addition, management believes that FFO provides useful information about the Company’s financial performance when compared to other REITs since FFO is generally recognized as the industry standard for reporting the operations of REITs. FFO should neither be considered as an alternative for net income as a measure of profitability nor is it comparable to cash flows provided by operating activities determined in accordance with GAAP. FFO is not comparable to similarly entitled items reported by other REITs that do not define them exactly as we define FFO.

PROPERTY AND OTHER DATA:Three MonthsEnded

Jun 30, 2011

Three MonthsEnded

Jun 30, 2010

Six MonthsEnded

Jun 30, 2011

Six MonthsEnded

Jun 30, 2010

Total properties, end of period 111 112 111 112

Total square feet, end of period 8,011,026 8,088,923 8,011,026 8,088,923

Average monthly rental revenue per square foot (3) $1.29 $1.31 $1.34 (7) $1.32

Occupancy for leased properties 66.5% 64.1% 66.5% 64.1% Straight-line rent $260 $9 ($375) ($228) Leasing commissions $128 $445 $323 $445

Non-recurring capital expenditures $613 - $1,539 -

LEASE ROLLOVER SCHEDULE:

Year

# of Leases

Rentable Square Feet

2011 Base Rent (5)

2011 (4)

6

284,099

$7,369,853

2012

12

784,393

15,046,671

2013

6

339,123

4,971,350

2014

21

1,677,913

26,653,825

2015

8

587,437

9,178,833

2016

7

275,251

4,280,551

2017

10

606,553

7,831,158

2018

3

265,612

1,120,944

2019

1

165,000

2,931,834

Thereafter

3

208,768

4,327,563

Total 77 5,194,149 $83,712,582

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BALANCE SHEETSJune 30, 2011 December 31, 2010

Assets

Investments in real estate:

Land $322,076 $322,076

Buildings and improvements 791,963 790,424

Real estate related intangible assets 1,121 3,240

Total investments in properties 1,115,160 1,115,740

Accumulated depreciation and amortization (233,578) (224,027) Assets held for sale, net 3,267 3,267

Net investments in properties 884,849 894,980

Investment in unconsolidated joint venture 3,698 3,830

Net investments in real estate 888,547 898,810

Cash and cash equivalents - 3,988

Restricted cash - 6,892

Deferred rent 17,566 17,941

Other assets, net 41,866 40,653

Total assets $947,979 $968,284

Liabilities:

Liabilities and Equity

Mortgage notes payable

$338,566

$345,770

Mortgage note payable – related parties

7,436

7,721

Interest payable

1,614

1,659

Security deposits

4,385

4,605

Prepaid rent

4,402

6,526

Dividends and distributions payable

13,687

15,793

Accounts payable and accrued expenses

18,492

16,239

Total liabilities

388,582

398,313

Commitments and contingencies.

Equity:

Stockholders’ equity:

Common stock, $.001 par value

22

22

Additional paid-in capital

175,863

172,568

Distributions in excess of accumulated earnings

(32,086)

(30,520)

Total stockholders’ equity

143,799

142,070

Noncontrolling interests in operating partnerships

415,598

427,901

Total equity

559,397

569,971

Total liabilities and equity

$947,979

$968,284

(1) Includes approximately $56 and $301 in amortization expense for the three months ended June 30, 2011 and 2010, respectively, and $180 and $461 in amortization expense for the six months ended June 30, 2011 and 2010, respectively, for the amortization of in-place lease value intangible asset pursuant to the Business Combinations Topic of the Financial Accounting Standards Board Accounting Standards Codification.

(2) Calculated on a fully diluted basis. Assumes conversion of all O.P. units outstanding into the Company’s common stock.

(3) Average monthly rental revenue per square foot has been determined by taking the cash base rent for the period divided by the number of months in the period, and then divided by the average occupied square feet in the period.

(4) Excludes five month-to-month leases for approximately 78,000 rentable square feet and approximately $106 in cash rent. (5) Base rent reflects cash rent.

(6) Includes a one-time rent adjustment of approximately $1,638 from a tenant dispute resolution.

(7) Includes a one-time rent adjustment of approximately $1,638. Excluding the adjustment, the average monthly rental revenue per square foot would have been $1.29.

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