Ocean Rig UDW Inc. Announces acceptance
by Petrobras of the ocean rig Corcovado

Nicosia, Cyprus – May 16, 2012


Ocean Rig UDW Inc. (the “Company” or “Ocean Rig”), (NASDAQ: ORIG) a global provider of offshore deepwater drilling services, today announced that on May 15, 2012, the Ocean Rig Corcovado completed the general testing of equipment as required by Petroleo Brazilieiro S.A., and has commenced revenue-generating drilling operations in Brazil.

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, 3 of which remain to be delivered to the company during 2013. Visit the Company’s website at www.ocean-rig.com.

Ocean Rig press release