The presidential mandate that agency rule makings be subjected to costbenefit analysis and regulatory review is one of the most controversial developments in administrative law over the past several decades. There is a prevailing view that the role of cost-benefit analysis in the executive branch is to help facilitate control of agencies by the Office of Information and Regulatory Affairs (OIRA). This Article challenges that view, arguing that cost-benefit analysis in fact helps preserve agency autonomy in the face of oversight. This effect stems from the constraints imposed on reviewers by the regularization of cost-benefit-analysis methodology and the fact that agencies have played a major role in shaping that methodology. The autonomy-preserving effect of cost-benefit analysis has been largely ignored in debates over the institution of regulatory review. Ultimately, cost-benefit analysis has ambiguous effects on agency independence, simultaneously preserving, informing, and constraining agency power.