The current study examined the role that exposure to natural human sweat has on heterosexual and homosexual men’s perceptions of sexual attractiveness. Seventy-two participants were included in the study. Participants engaged in 3 tasks; the first was to provide health history and sexual orientation information, the second task was to view photographs of men and women, and the third was to rate the previous images on level of attractiveness. The photograph viewing and rating tasks were done while participants were exposed to either human male underarm sweat, female Day-14 of the menstrual underarm sweat, female Day-27 of the menstrual cycle underarm sweat, or no sweat, using a small fan that blew air over the sweat pad and onto the participants face. Photographs of male and female faces were rated significantly lower by heterosexual men exposed to male underarm sweat. Heterosexual men rated photographs of female faces significantly higher than male faces in both the Day-14 and Day-27 female sweat conditions. Homosexual men showed no preference for male photographs in the male sweat versus no sweat conditions.