OBJECTIVE: The prevalence and characteristics of childhood sexual abuse (CSA) among men who have sex with men (MSM), and links with sexual risk are explored. A model linking CSA and sexual risk among MSM is proposed. METHOD: A telephone probability sample of urban MSM (n = 2881) was recruited and interviewed between November 1996 and February 1998. The interview covered numerous health issues, including history of sexual victimization. RESULTS: One-fifth reported CSA, primarily by non-family perpetrators. Initial CSA experiences are characterized by high levels of force (43% involved physical force/weapons), and penetrative sex (78%; 46% reported attempted or actual anal intercourse). Such men are more likely than nevercoerced men to engage in high risk sex (unprotected anal intercourse with a non-primary partner or with a serodiscordant male). In multivariate analyses, the effect of childhood sexual coercion on sexual risk is mediated by substance use, patterns of sexual contacts, and partner violence, but not by adult sexual revictimization or by depression. CONCLUSIONS: Findings are interpreted within the context of social learning theory and prior research on sexual risk-taking. The high risk for CSA among MSM, which can predispose such men to patterns of HIV sexual risk, warrants new approaches in HIV prevention.