Аннотация:Adolescent girls remain vulnerable to HIV and other sexually transmitted infections. Understanding their sexual and substance use behaviors is essential to designing effective interventions to reduce their risk. In this study, baseline data were analyzed from 738 adolescent girls ages 15 to 19 years in Rochester, New York. Data on sexual behavior and substance use (lifetime, past 3 months, and most recent sexual experience) were collected. Nearly one half of recent vaginal (42%) and anal (45%) sex acts were not condom protected; 39% had a prior sexually transmitted infection (STI) and 12% were currently infected with an STI. Approximately one third (31%) of girls had more than one sex partner in the past 3 months. Girls with multiple partners reported that their recent sexual experiences were more likely to involve drug and alcohol use by themselves and partners. Adolescent girls, particularly those with multiple sexual partners, continue to report high-risk sexual behaviors and need focused risk-reduction interventions.