Previous research documents the co-occurrence of substance use and HIV risk behaviors, but most studies examined these behaviors among adults and White adolescents. The diversity of Florida's adolescents presents a unique setting for examining the variations in these risk behaviors. An in-depth analysis of HIV and substance use behaviors among White, African American, and Hispanic adolescents in Florida was conducted. Results suggest that significant ethnic variations exist in lifetime alcohol and illicit drug use and HIV risk. Compared with Hispanics, African Americans were less likely and Whites were more likely to be frequent alcohol and illicit drug users. White and African American adolescents were 1.3 and 1.5 times, respectively, at higher risk of at least one HIV risk behavior compared with their Hispanic counterparts. Future research should seek to identify sources and consequences of such variations in risk behavior and design culturally appropriate prevention programs for adolescents.