Sexual risk behavior has decreased among men who have sex with men in Los Angeles but remains greater than that among heterosexual men and women Surveys, a population-based telephone survey, were analyzed to examine the association of sociodemographic and health-related factors with sexual risk behaviors among the three groups. In each time period, MSM reported a significantly greater percentage of sexual risk (i.e., both inconsistent condom use and multiple sex partners in the past 12 months) compared with heterosexual men and women. Multivariate analyses indicated that MSM and heterosexual men reported greater sexual risk than heterosexual women. Respondents who were younger, U.S. born, reported heavy alcohol consumption, or had been tested for HIV in the past 24 months were more likely to report sexual risk behavior. The findings suggest the need for continued targeted prevention for MSM and prevention efforts for segments of the general population at elevated risk for HIV.In the United States HIV continues to disproportionately impact men who have sex with men (MSM), particularly when compared with heterosexual men and women. Recent data indicate that the incidence of new HIV infections and AIDS diagnoses among MSM continues to vastly exceed those of heterosexual men and women (Centers for Disease Control and Prevention [CDC], 2007). Nationally, MSM make up the largest proportion (39%) of new infections, compared with 5% and 12% for 312