Russia is experiencing one of the sharpest increases in HIV incidence in the world. Almost no research has examined patterns of risk behavior among Russian men who have sex with men (MSM). A total of 434 MSM were surveyed in all of St. Petersburg's gay-identified clubs during June 2000. Men completed questionnaires about their sexual practices, AIDS risk knowledge, safer sex attitudes, behavior change intentions, perceived safer sex norms, and fatalism. Most MSM were bisexual; 79% had female partners in their lives and 37% had female partners in the previous 3 months. Sexually transmitted disease treatment was reported by 32% of the men, 23% had sold sex to gain money, and knowledge about critical HIV risk-reduction steps was low. Of all men surveyed, 38% had unprotected anal sex in the previous 3 months, consistent condom use was reported by only 30% of men, and most recent anal intercourse occasions 37% of particpants'. Regression analyses showed that high-risk behavior was predicted by poor safer sex attitudes, weak behavior change intentions, low knowledge about AIDS risk, perceived peer norms that did not support safer sex, and having a boyfriend. To avert a widespread epidemic, HIV prevention interventions for Russian MSM are critically needed. Factors predicting risk were consistent with those found among MSM in other countries early in the HIV epidemic. However, unique cultural factors, including frequent bisexual behavior, the 'newness' of openly gay communities in Russia and lack of community experience in dealing with AIDS, require HIV prevention program tailoring.