Two studies are presented that evaluate newly developed scales of sensation seeking and sexual compulsivity. Results showed that the scales were reliable and correlated with convergent and divergent measures in expected directions in samples of both gay men (N = 296) and inner city low-income men and women (N = 158). Consistent with theories of sensation seeking, the scales corresponded to an attraction toward a range of sexual practices, including increased frequencies of unprotected intercourse and a greater number of sexual partners. As expected, sexual compulsivity was not related to variety and novelty in sexual practices, but was associated with lower levels of self-esteem and resistance to adopting sexual risk-reducing strategies. However important differences were observed between the gay men and heterosexual samples; scales correlated with substance use only among gay men, and sexual compulsivity was related to a range of sexual practices only among heterosexuals. The sensation seeking and Sexual Compulsivity Scales were therefore reliable, appeared valid, and useful in predicting sexual risk behaviors.