Ocean Rig UDW Inc. Announces Commencement of "When Issued" Trading on the Nasdaq Global Select Market

   Ocean Rig UDW Inc. (NASDAQ: ORIGV) (NASDAQ: ORIG) (the "Company" or "Ocean Rig"), a global provider of offshore deepwater drilling services, announced that its common shares are expected to commence "when issued" trading today on the Nasdaq Global Select Market under the ticker symbol "ORIGV." The Company's common shares are expected to commence "regular way" trading on the Nasdaq Global Select Market under the ticker symbol "ORIG" on October 6, 2011, the next trading day after the distribution date for the partial spin off of October 5, 2011.

About Ocean Rig Ocean Rig is an international offshore drilling contractor providing oilfield services for offshore oil and gas exploration, development and production drilling, and specializing in the ultra-deepwater and harsh-environment segment of the offshore drilling industry. The company owns and operates 9 offshore ultra deepwater drilling units, comprising of 2 ultra deepwater semisubmersible drilling rigs and 7 ultra deepwater drillships, 4 of which remain to be delivered to the company during 2011 and 2013.

Visit the Company's website at www.ocean-rig.com.

Forward-Looking Statements

Matters discussed in this release may constitute forward-looking statements. Forward-looking statements relate to Ocean Rig's expectations, beliefs, intentions or strategies regarding the future. These statements may be identified by the use of words like "anticipate," "believe," "estimate," "expect," "intend," "may," "plan," "project," "should," "seek," and similar expressions. Forward-looking statements reflect Ocean Rig's current views and assumptions with respect to future events and are subject to risks and uncertainties.

The forward-looking statements in this release are based upon various assumptions, many of which are based, in turn, upon further assumptions, including without limitation, management's examination of historical operating trends, data contained in Ocean Rig's records and other data available from third parties. Although Ocean Rig believes that these assumptions were reasonable when made, because these assumptions are inherently subject to significant uncertainties and contingencies which are difficult or impossible to predict and are beyond Ocean Rig's control, Ocean Rig cannot assure you that it will achieve or accomplish these expectations, beliefs or projections described in the forward-looking statements contained herein. Actual and future results and trends could differ materially from those set forth in such statements.

Important factors that, in Ocean Rig's view, could cause actual results to differ materially from those discussed in the forward-looking statements include (i) factors related to the offshore drilling market, including supply and demand, utilization, day rates and customer drilling programs; (ii) hazards inherent in the drilling industry and marine operations causing personal injury or loss of life, severe damage to or destruction of property and equipment, pollution or environmental damage, claims by third parties or customers and suspension of operations; (iii) changes in laws and governmental regulations, particularly with respect to environmental matters; (iv) the availability of competing offshore drilling vessels; (v) political and other uncertainties, including risks of terrorist acts, war and civil disturbances; piracy; significant governmental influence over many aspects of local economies, seizure; nationalization or expropriation of property or equipment; repudiation, nullification, modification or renegotiation of contracts; limitations on insurance coverage, such as war risk coverage, in certain areas; political unrest; foreign and U.S. monetary policy and foreign currency fluctuations and devaluations; the inability to repatriate income or capital; complications associated with repairing and replacing equipment in remote locations; import-export quotas, wage and price controls imposition of trade barriers; regulatory or financial requirements to comply with foreign bureaucratic actions; changing taxation policies; and other forms of government regulation and economic conditions that are beyond our control; (vi) the performance of our rigs; (vii) our ability to procure or have access to financing and comply with our loan covenants; (viii) our ability to successfully employ our drilling units; (ix) our capital expenditures, including the timing and cost of completion of capital projects; and (x) our revenues and expenses. Due to such uncertainties and risks, investors are cautioned not to place undue reliance upon such forward-looking statements.

Contact: Investor Relations / Media: Nicolas Bornozis Capital Link, Inc. (New York) Tel. [phone] E-mail: [e-mail]