HIV remains a critical health issue for men who have sex with men (MSM). In the United States, an estimated 365,000 to 535,000 MSM are living with HIV, and 42% of new HIV infections occur in this population. Recent data on sexually transmitted diseases and on sexual behavior indicate the potential for a resurgence in HIV infections among MSM. Outbreaks of gonorrhea and syphilis have been reported in a growing number of cities, and several studies have observed an increase in unprotected anal intercourse among MSM. These increases in HIV risk behavior may be attributed to several factors that have affected the sexual practices of MSM, including changes in beliefs regarding the severity of HIV disease. These emerging data have implications for surveillance and intervention research activities and indicate a need to reevaluate, refocus, and reinvigorate HIV prevention efforts for MSM. Our recommendations for addressing the HIV prevention needs of MSM include the need to consider HIV-related issues within the broader context of the physical, mental, and sexual health of MSM.