This study examines patterns of sexual behavior, sexual relating, and sexual risk among HIV-positive men sexually active with women. A total of 278 HIV-positive men were interviewed every 6-12 months between 1994 and 2002 and reported considerable variability in sexual behaviors over time. Many were not sexually active at all for months at a time; many continued to have multiple female and at times male partners. Over one-third of the cohort had one or more periods when they had engaged in unprotected sex with a female partner who was HIV-negative or status unknown (unsafe sex). Periods of unsafe sex alternated with periods of safer sex. Contextual factors such as partner relations, housing status, active drug use, and recently exchanging sex showed the strongest association with increased odds of unsafe sex. A number of predictors of unsafe sex among African American men were not significant among the Latino sub-population, suggesting race/ethnic differences in factors contributing to heterosexual transmission. Implications for prevention interventions are discussed.