This study focuses on psychological differences in risk-taking patterns and their association with risk compensation motivations in the context of pre-exposure prophylaxis (PrEP). Participants were 257 HIV-negative MSM and transgender women recruited in New York City. The majority of participants (89.5 %, n = 230), could be classified as either: Intimates (40 %), who report unprotected anal intercourse (UAI) only with a main partner believed to be HIV-negative; Trusters (34 %), who engaged in UAI only with casual partners believed to be HIV-negative; and Gamblers (26 %) who report UAI with partners of unknown serostatus. Partner-based classifications were better predictors of HIV risk perception and other traditional correlates of risk-taking (e.g. impulsivity, sexual compulsivity) than rates of UAI. The three groups differed significantly in PrEP-related risk compensation motivations: sexual pleasure (Gamblers), intimacy (Trusters) and partner pressure (Intimates). These data underscore the importance of focusing the psychological dynamics of risk perception and sexual decision-making.