In a test of the hypothesis that a difference exists between males and females in motives for participating in sexual intercourse, a random sample of 249 college students was given a questionnaire containing questions about sexual behavior and attitudes, focusing on motives for having intercourse. There were significant differences between males and females in approval of casual sexual intercourse, number of premarital sexual partners, most important part of sexual behavior, and whether an emotional involvement was a prerequisite for participating in sexual intercourse. Effect-size analyses indicated that these differences are large, with a median omega 2 = 0.24. Both males and females approved of premarital sexual intercourse in a serious relationship and stressed the importance of feeling loved and needed. However, males found it easier to participate in sexual intercourse without an emotional commitment, whereas females were unlikely to want intercourse for physical pleasure in the absence of psychological involvement.