This study assessed the prevalence of various HIV-associated risk behaviors among men who have sex with men (MSM) attending a popular sex resort in the southern United States. One hundred fifty men completed an anonymous self-administered questionnaire (91% response rate). Men currently resided in 14 states. One sixth reported being HIV-positive. During a typical resort visit, men averaged 4 sex partners. About two thirds of the men had anal sex during a typical resort stay; of these, 21% reported never using condoms and 41% reported always using condoms. HIV risk behavior over the past few months was also assessed. Men averaged 10 sex partners. Meeting partners by means of the Internet (57%) and bathhouses-excluding sex resorts-(40%) was common. Most men (62%) reported having group sex. About one half (49%) engaged in unprotected anal sex. Significant differences in recent frequency of unprotected anal sex between HIV-positive and HIV-negative men were not found (P = 0.74). Among those using condoms, 20% reported not using condoms from start to finish of sex, 7% reported breakage, and 6% reported slippage. Twenty-three percent had anal sex without lubrication. Fisting and the use of nonprescription sildenafil citrate (Viagra) was reported by about one sixth of the men. The findings suggest that MSM attending sex resorts may experience substantial risk of HIV infection. Sex resorts may be an important venue for HIV prevention.