Editors' Summary: Environmental statutes frequently leave important policy and implementation issues to subsequent rulemaking by the Environmental Protection Agency. In practice, however, the EPA does not have a free hand in promulgating regulations; it has often needed to convince the Office of Management and Budget (OMB) of the wisdom of its proposals. In this article, the author outlines the legal basis of OMB involvement and describes the strengths and weaknesses flowing from OMB's authority. He notes that although vigorous oversight in the political process will continue as a key check on OMB, recent litigation also suggests areas in which courts may be willing to intervene.