Across HIV prevention studies, as many as 25% of men who have sex with men (MSM) report meeting male partners at private sex events and attendance is associated with increased number of sexual partners, condomless anal sex (CAS), and HIV infection. Despite the need for effective HIV prevention interventions, no risk reduction interventions have been tested to reduce HIV sexual risk of MSM that regularly engage in sexual risk at private sex events. This randomized pilot study assessed the feasibility and acceptability of an HIV risk reduction intervention to reduce CAS among urban MSM (N = 14) reporting risk at a private sex event in the prior 12 months. The intervention arm received four group sessions (2 h/session) focusing on HIV risk reduction education and skills building. Both the intervention (n = 8) and control (n = 6) conditions received HIV testing and pre- and posttest risk reduction counseling and completed a sexual risk and psychosocial assessment visit at baseline and 3 months post-intervention. In addition, intervention participants completed a brief exit interview post-intervention. Mean age was 37 years, and 57% were racial/ethnic minorities. At follow-up, the intervention group reported greater reductions in sexual risk behavior in the past 3 months including number of CAS episodes, number of partners at private sex events, and CAS episodes at private sex events. The intervention group also reported reduced sexual compulsivity, increases in HIV disclosure, and reduced drug use at private sex events over study follow-up. Exit interviews revealed that participants found the intervention to be highly acceptable. Findings demonstrate feasibility of procedures, participant acceptability, and initial promise of a group-delivered HIV risk reduction intervention for MSM who attend and engage in CAS at private sex events. Further testing of this intervention in a larger pilot randomized controlled trial is warranted.