In April 2007, the Centers for Disease Control and Prevention (CDC) held a two-day consultation with a broad spectrum of stakeholders to obtain input on the potential role of male circumcision (MC) in preventing transmission of human immunodeficiency virus (HIV) in the U.S. Working groups summarized data and discussed issues about the use of MC for prevention of HIV and other sexually transmitted infections among men who have sex with women, men who have sex with men (MSM), and newborn males. Consultants suggested that (1) sufficient evidence exists to propose that heterosexually active males be informed about the significant but partial efficacy of MC in reducing risk for HIV acquisition and be provided with affordable access to voluntary, high-quality surgical and risk-reduction counseling services; (2) information about the potential health benefits and risks of MC should be presented to parents considering infant circumcision, and financial barriers to accessing MC should be removed; and (3) insufficient data exist about the impact (if any) of MC on HIV acquisition by MSM, and additional research is warranted. If MC is recommended as a public health method, information will be required on its acceptability and uptake. Especially critical will be efforts to understand how to develop effective, culturally appropriate public health messages to mitigate increases in sexual risk behavior among men, both those already circumcised and those who may elect MC to reduce their risk of acquiring HIV.