This study used elements of social cognitive theory to examine the relationship between partner type and sexual risk behavior in a sample of HIV positive gay and bisexual men. Self-efficacy captures one's perceived ability to perform a behavior; outcome expectancies are estimations that a behavior will result in a given outcome. An examination of sexual risk behavior revealed that men with steady partners and men with anonymous partners had the most unprotected anal intercourse (UAI), while men with casual partners had the least. Men with anonymous partners had the lowest scores on self-efficacy and outcome expectancies for condom use, negotiation, and disclosure. Outcome expectancies for negotiation of safer sex were inversely related to UAI for men with steady partners. Self-efficacy for condom use and negotiation were inversely related to UAI for men with casual partners. These findings suggest the need to consider partner type in the development of sexual risk reduction interventions.