Previous studies have suggested high rates of HIV infection and other sexually transmitted infections in theU.S.-Mexico border region. However, no information is available on the risk for HIV infection among Mexican adolescents living in this geographic area. This study examines the prevalence of HIV risk practices and psychosocial correlates among 370 high school students in the border city of Tijuana, Mexico, by gender and age group. The results indicate substantial risk for HIV infection among Tijuana youth due to unprotected sexual practices, lifetime rates of pregnancy and sexually transmitted infections, and needle-sharing practices, mostly related to tattooing and body piercing. These findings suggest the need for HIV prevention programs for Tijuana adolescents. These programs must be culturally sensitive and tailored to meet the needs of the different age and gender groups in this region.