BACKGROUND: This study examined the feasibility of a combination prevention intervention for young men who have sex with men (YMSM), an anticipated target population for HIV preexposure prophylaxis (PrEP). METHODS: Project PrEPare, a pilot study using a randomized 3-arm design, compared an efficacious behavioral HIV prevention intervention (Many Men, Many Voices-3 MV) alone, 3 MV combined with PrEP (tenofovir/emtricitabine), and 3 MV combined with placebo. Eligible participants were 18- to 22-year-old HIV-uninfected men who reported unprotected anal intercourse in the past year. Participants were screened for preliminary eligibility at youth venues and community organizations and were also referred through social networks. Laboratory screening determined final eligibility. Behavioral and biomedical data were collected at baseline and every 4 weeks thereafter for 24 weeks. RESULTS: Sixty-eight youth (mean age = 19.97 years; 53% African American, 40% Latino) were enrolled; 58 were randomized. Self-reported medication adherence averaged 62% (range, 43%-83%), whereas rates of detectable tenofovir in plasma of participants in the emtricitabine/tenofovir disoproxil fumarate arm ranged from 63.2% (week 4) to 20% (week 24). There were 5 >/= grade 2 adverse events possibly/probably related to the study medication. Sexual risk behavior declined from baseline to week 24 in all study arms. CONCLUSIONS: The feasibility of enrolling at-risk youth, particularly young men who have sex with men of color, into Project PrEPare has been demonstrated. The acceptability of the group intervention along with counseling and testing was high. Self-reported medication adherence and corresponding plasma drug concentrations were low indicating the need for enhanced adherence counseling. Exploration of PrEP use among youth in nonrandomized open label trials is warranted.