Digital Realty Trust Completes New Lease Agreement With IBM

Digital Realty Trust Completes Second Turn-Key DatacentreSM Lease Agreement with IBM in Paris

Paris, France and London, UK – April 28, 2009 – Digital Realty Trust, Inc. (NYSE: DLR), the world’s largest wholesale datacentre provider, has completed a second Turn-Key DatacentreSM lease agreement with IBM for space at Digital Realty Trust’s suburban Paris facility. Under this agreement, IBM will expand its datacentre accommodation capacity in the Digital Realty Trust facility to support growth in demand for its services. The prior agreement was announced in October 2008.

“Our goal is to be a true partner to our customers, by supporting their datacentre strategy and ensure the expansion of their IT teams and facilities through our expertise and resources. This new agreement with IBM in France consolidates our relationship and we are proud to be collaborating with them once again on an important datacentre project,” said Bernard Geoghegan, Senior Vice President of International Operations of Digital Realty Trust. “Our Turn-Key DatacentreSM space enables customers to reduce the upfront capital costs for these critical projects while accelerating their ability to deploy new systems. These are very compelling reasons for companies to select Digital Realty Trust as their datacentre partner.”

Digital Realty Trust Turn-Key DatacentreSM facilities provide state-of-the-art environments to house mission critical infrastructure, by providing advanced cooling, power, redundancy, and sustainability features. This guarantees that critical applications are available while optimising energy efficiency. Digital Realty Trust’s Turn-Key DatacentresSM are scalable from hundreds of kilowatts of IT Load to megawatts of IT load and are located in markets throughout Europe and North America. Each Turn-Key DatacentreSM facility is physically secure and features a state-of-the-art power and cooling architecture that has been optimised for green operation. Every Turn-Key DatacentreSM is built using the company’s proprietary POD ArchitectureSM and uses metered power to ensure that clients pay only for the power that they use.

About Digital Realty Trust, Inc.

Digital Realty Trust owns, acquires, redevelops, develops and manages technology-related real estate. The Company is focused on providing Turn-Key DatacenterSM and Powered Base BuildingSM datacenter solutions for domestic and international tenants across a variety of industry verticals ranging from information technology and internet enterprises, to manufacturing and financial services. Digital Realty Trust’s 75 properties, excluding one property held as an investment in an unconsolidated joint venture, contain applications and operations critical to the day-to-day operations of technology industry tenants and corporate enterprise datacenter tenants. Comprising approximately 13.0 million square feet as of February 26, 2009, including 1.6 million square feet of space held for redevelopment, Digital Realty Trust’s portfolio is located in 27 markets throughout Europe and North America. For additional information, please visit Digital Realty

Trust’s website at http://www.digitalrealtytrust.com.

Safe Harbor Statement

This press release contains forward-looking statements which are based on current expectations, forecasts and assumptions that involve risks and uncertainties that could cause actual outcomes and results to differ materially. These risks and uncertainties include adverse economic or real estate developments in the Company’s markets; general economic slow-downs or recessions; reductions in information technology spending; difficulties in or inability to lease space, including redeveloped space; construction and development delays; increased development costs; tenant bankruptcies or defaults under leases by tenants; failure to commence rental payments on time under signed leases; increased interest rates; increased operating costs; failure to obtain necessary outside financing; decreased rental rates or increased vacancy rates; difficulties in identifying properties to acquire; completing acquisitions at all or at acceptable return levels; failure to successfully operate properties; failure of existing, acquired or redeveloped properties to perform as expected; reductions in property values; failure to maintain the Company’s status as a REIT; environmental uncertainties and risks related to natural disasters; financial market fluctuations; changes in foreign currency exchange rates; risks of operating in foreign markets; and changes in real estate and zoning laws and increases in real property tax rates. For a further list and description of such risks and uncertainties, see the reports and other filings by the Company with the United States Securities and Exchange Commission, including the Company’s annual report on Form 10-K for the year ended December 31, 2008. The Company disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

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For Additional Information:

A. William Stein

Chief Financial Officer and

Chief Investment Officer

Digital Realty Trust, Inc.

+1 415-738-6500

Pamela A. Matthews

Investor/Analyst Information

Digital Realty Trust, Inc.

+1 415-738-6500

Bernard Geoghegan

Senior Vice President

International Operations

Digital Realty Trust, Inc.

+353 (1) 2450650