This research report details the impact findings from the evaluation of three replications of the Safer Sex Intervention (SSI), a clinic-based intervention intended to reduce the incidence of sexually transmitted infections (STIs) and increase condom use among high-risk sexually active female adolescents. The study examined data from three different replications of SSI, pooling the data to examine the overall program impact. Interim findings from the 9-month follow-up indicated a positive impact on young women’s use of birth control when they engaged in sexual intercourse: program participants were 6% less likely to have unprotected sex than non-participants. At the 18-month follow-up, this effect was smaller and no longer significant, although there was still a 3% difference in the incidence of unprotected sex between program participants and non-participants. At the 18-month follow-up, there was a promising effect on pregnancy that was not statistically significant (p=.07): fewer program participants reported a pregnancy compared to non-participants (16% vs. 19.4%). Across all three replications, SSI was delivered with fidelity to its key elements and sites retained the majority of program participants over the six-month intervention period. The report also details findings for non-behavioral intermediate outcomes (i.e., knowledge, attitudes and intentions) and results from exploratory analyses examining differences in impacts by site and by subgroup (e.g., by age and sexual experience at baseline).