This study explores the relationship between male sexual behavior and personality factors, as measured by the MMPI and Sensation Seeking Scale. Subjects were 20 male volunteers, ages 19–58, with a history of long-term sexual relationships. Subjects kept a daily record of sexual behaviors. Frequency of these behaviors was correlated with MMPI and Sensation Seeking (SSS) subscales. Results indicate that both introversion and depression show significant correlations with autoerotic stimulation and arousal, but not with heterosexual activity. There is no significant correlation demonstrated between hypomania and sexual activity. The Boredom Susceptibility subscale of the SSS correlated significantly with the number of sexual partners.