This paper reports on a study that developed a model of sexual risk-taking behavior that included psychological measures, as well as social or demographic factors, and contextual variables. The study seeks to contribute to the knowledge based used when designing health promotion or disease prevention programs that promote safer sexual practices among young Americans. Study participants (n=613) completed an anonymous self-report survey in late 1995. The "Theory of Planned Behavior" is applied as a theoretical framework for the development of a model of sexual risk-taking behaviors that includes psychological measures as well as social and demographic factors and contextual variables. An overview of the theory and discussion of the operationalization of variables is presented. Results indicate that perceived social norms consistently predict safe sex behavior both directly as well as mediating the influence of some of the psychological variables on behavior. Therefore, promoting an environment in which safe sex is the norm appears to be a powerful means to reduce high-risk sexual behavior. Future research needs are discussed. (Author/EMK)