In the current study, a battery of self-report measures of impulsivity, self-esteem, and depressive symptoms, as well as a behavioral measure of risk-taking propensity, was administered to 76 residents of two inner-city substance use residential treatment programs to determine the unique relationship between risk-taking propensity and risky sexual behavior (RSB). Results indicated that impulsivity, self-esteem, and risk-taking propensity were independently related to RSB. In a subsequent regression analysis, risk-taking propensity evidenced incremental validity, suggesting a relationship between risk-taking propensity and RSB, above and beyond that provided with the other relevant variables. The potential importance of risk-taking propensity the better understanding HIV risk through engagement in RSB is discussed.