1 EXHIBIT 21 SUBSIDIARIES OF THE REGISTRANT The following is a list of subsidiaries of the Registrant: Registrant and Parent: Rowan Companies, Inc. Wholly-Owned Subsidiaries of Registrant: Era Aviation, Inc., a Washington corporation Rowan International, Inc., a Panamanian corporation Rowandrill, Inc., a Texas corporation Atlantic Maritime Services, Inc., a Texas corporation Rowan Petroleum, Inc., a Texas corporation LeTourneau, Inc., a Texas corporation Note: Certain subsidiaries have been omitted from this listing because such subsidiaries, when considered in the aggregate as a single subsidiary, would not constitute a significant subsidiary.