The search for possible causal mechanisms leading to unprotected intercourse in males is the current focus of a great deal of psychosocial research. A retrospective questionnaire study of male undergraduate students (N = 332) examined the role of alcohol use and risk-taking behavior as a contributor to unprotected intercourse. Respondents' degree of risk-taking behavior during various periods of their life, and their alcohol use patterns and unprotected intercourse during their freshman and senior years of college were analyzed by a structural model. Results indicate a good model fit and suggest that older adolescent/young adult males may engage in riskier sexual behavior when using alcohol. Additionally, specific early behavior patterns appear to be the best predictor, from the variables in our model, of subsequent behavior. The findings of this study and other studies demonstrate that safe-sex instructional techniques designed for adolescents and young adults may benefit by focusing partly on responsible alcohol use.