Risk compensation has been called the “Achilles’ heel” of HIV prevention policies (Cassell et al., 2006). This paper examines the behavioral response to male circumcision, a major HIV prevention policy currently being implemented throughout much of Sub-Saharan Africa. Contrary to the presumption of risk compensation, we find that the response due to the perceived reduction in HIV transmission appears to have been a reduction in risky sexual behavior. We suggest a mechanism for this finding: circumcision may reduce fatalism about acquiring HIV/AIDS and increase the salience of the tradeoff between engaging in additional risky behavior and avoiding acquiring HIV. We also find what appears to be a competing effect that does not operate through the circumcision recipient's belief about the reduction in the risk of acquiring HIV.