OBJECTIVE Mediators of childhood sexual abuse (CSA) and HIV risk behavior were examined for men-who-have-sex-with-men (MSM). METHODS Data from a dual frame survey of urban MSM (N=1078) provided prevalence estimates of CSA, and a test of two latent variable models (defined by partner type) of CSA-risk behavior mediators. RESULTS A 20% prevalence of CSA was reported. For MSM in secondary sexual relationships, our modeling work identified two over-arching but inter-related pathways (e.g., both pathways include effects on interpersonal skills) linking CSA and high-risk behavior: (1) CSA-Motivation-Scripts-Skills-Risk Behavior; and (2) CSA-Motivation-Coping-Risk Appraisal-Skills-Risk Behavior. For men in primary relationships, there was one over-arching pathway including CSA-Motivation-Coping-Risk Appraisal-Risk Behavior processes. Exploratory analyses indicated that men with a history of CSA in only primary relationships versus only secondary relationships had, for example, fewer motivational problems, and better coping and interpersonal skills. CONCLUSIONS CSA contributes to the ongoing HIV epidemic among MSM by distorting or undermining critical motivational, coping, and interpersonal factors that, in turn, influence adult sexual risk behavior. Further, the type of adult relationships men engage in serve as markers for adult CSA-related problems. The findings are discussed in the context of current theory and HIV prevention strategies. CONCLUSIONS Direct extrapolation from our findings to practice is limited. However, there are general implications that may be drawn. First, the complex challenges faced by men with severe CSA experiences may limit the effectiveness of typical short-term HIV risk reduction programs; more intensive treatment maybe needed. Secondly, Clinical Psychologists and Psychiatrists with MSM patients with CSA histories should, if not already, routinely consider issues of sexual health; patterns and types of sexual partners may be useful markers for identifying more problematic cases. Lastly, public service messages directed at destigmatizing CSA for MSM may increase use of health and mental health services.