Adolescence is the only age category where the number of females infected with HIV outnumber the number of males. Despite these data, only three randomized controlled trials have evaluated the efficacy of a gender-specific HIV-risk reduction program for adolescent females. The proposed research aims to address this gap in HIV prevention science, and will evaluate the short and longer-term efficacy of a HIV-prevention intervention for adolescent girls. We will recruit 640 adolescent females aged 15 to 19 years from family planning clinics and randomly assign them to one of two conditions: (a) an HIV-risk reduction intervention based on the Information-Motivation-Behavioral Skills (IMB) model (Fisher & Fisher, 1992) or (b) a structurally equivalent health promotion control group (CTL) both supplemented by booster sessions at 3 and 6 months. At a short-term (3-month) follow-up, we hypothesize that IMB participants will increase HIV-related knowledge, motivation, and behavioral skills, and decrease the frequency of risky sexual practices relative to CTL participants. We will reassess all participants at 6 and 12 months to evaluate the longer-term efficacy of the interventions. At these longer-term follow-ups, we hypothesize that IMB participants will demonstrate higher levels of HIV knowledge, motivation, and behavioral skills; decreased risky sexual practices; and decreased rates of STDs (Chlamydia, gonorrhea) relative to the CTL participants. The final aim of the proposed research is to determine whether the constructs in the Information-Motivation-Behavioral Skills (IMB) Model (Fisher & Fisher, 1992), can account for variability in HIV-related behavior. We hypothesize that preventive behavior at 6 and 12 months will be a function of a participant's HIV-related information, motivation, and behavioral skills at the 3-month follow-up, and that information and motivation will be partially mediated by behavioral skills to influence the initiation and maintenance of HIV preventive behavior. The long-term intent of the proposed research is to develop a risk reduction program that can be used by community-based health organizations to reduce the risk of HIV infection among adolescent females.