Although levels of knowledge about AIDS and human immunodeficiency virus (HIV) transmission were uniformly high prior to intervention, at least 60 percent of the men reported having engaged in unprotected, receptive anal intercourse with more than one partner in the preceding 6 months. Prior to intervention, a substantial number of the men had mixed feelings about AIDS risk reduction. After attending the session, attitudes improved significantly in five of the six areas surveyed. The ability of a group educational session to influence attitudes about AIDS risk reduction in a positive way suggests that this type of intervention may be effective in enabling homosexual and bisexual men to adopt low-risk sexual activities by influencing the nonhealth motives of sexual behavior, especially peer norms about safe sex. Long-term followup of this cohort will test for maintenance of this attitudinal change and, more importantly, will evaluate whether this attitudinal change is predictive of future changes in sexual behavior and HIV seroconversion rates. The authors stress the importance of incorporating existing health promotion research findings into the design and evaluation of AIDS risk reduction programs. (Publisher abstract)