This research investigates the impact adolescent substance use has on adult sexual risk behaviors within racial-ethnic groups. Previous research has found support for this relationship, but often relies on concurrent measures of substance use and sexual risk behavior. Therefore, the causal direction of this relationship may be unclear. The data for this study come from the National Longitudinal Survey of Adolescent to Adult Health (Add Health), a nationally representative survey that followed respondents from adolescence in 1994 to adulthood in 2008. Results show that substance use correlates with sexual risk behavior, but the impact varies by race-ethnicity.