Despite increasing rates of HIV infection among young men who have sex with men (YMSM), only a minority participate in formal HIV prevention efforts. Semi-structured mixed-methods interviews were conducted with a diverse sample of YMSM (N = 100, M[subscript age] = 25.0 years) in Los Angeles, California, to identify facilitators and barriers to participation in HIV prevention programs. Summative content analyses were used to evaluate transcribed field notes from these interviews. Results showed that 28.0% of all participants had previously attended an HIV prevention program, and that 21.3% of those who were also asked if they had ever participated in any research pertaining to HIV prevention had done so. A significantly higher percentage of those who had participated in HIV prevention programs had been tested for HIV in the past 6 months compared to those who had not (p less than 0.05). The most frequently mentioned barriers to participation in such a program were being too busy to attend (12.0%), not perceiving themselves to be at risk for HIV infection (14.0%), and believing that they already knew everything they needed to know about HIV transmission (23.0%). YMSM suggested that future interventions should use technology (e.g., the Internet, mobile devices), engage their social networks, and highlight HIV prevention as a means for community connection. Collectively, these results provide some explanations for why YMSM account for a minority of HIV prevention program participants and offer possible directions for future HIV prevention efforts that target YMSM.