Very little information exists with regard to sex party behaviors in young men who have sex with men (YMSM), often defined as men ranging in age from 13 to 29 years. The current analysis examines sex party attendance and behavior in a sample of 540 emergent adult gay, bisexual, and other YMSM in New York City, ages 18-29 years. Findings indicate that 8.7% (n = 47) of the sample had attended a sex party 3 months prior to assessment. Sex party attendees reported that parties included both HIV-positive and HIV-negative men; attendees also reported unprotected sex and limited access to condoms and lubricant. As compared with those who did not attend sex parties, those who did indicated significantly more lifetime and recent (last 3 months) casual sex partners, drug use (both number of different drugs used and total lifetime use), psychosocial burden (history of partner violence and number of arrests), and total syndemic burden (a composite of unprotected anal sex, drug use and psychosocial burden). These results indicate that while only a small percentage of the overall sample attended sex parties, the intersection of both individual risk factors coupled with risk factors engendered within the sex party environment itself has the potential to be a catalyst in the proliferation of the HIV/AIDS epidemic in urban settings. Lastly, given that sex parties are different than other sex environments, commercial and public, with regard to how they are accessed, public health strategies may need to become more tailored in order to reach this potentially highly risky group.