Objective: The beginning of college marks a decline in physical activity and racial/ethnic minorities have disproportionately lower rates of physical activity. This study examined the association between perceived stress and physical activity among an ethnically diverse sample of college-attending young adults. Participants: 2,396 students (36% male, 64% female) from a large public university. Methods: Cross-sectional survey administered across campus departments and general education courses. Results: Gender stratified multivariate analyses showed for both males and females, higher perceived stress was associated with less frequency of physical activity the past six months. Compared to non-Hispanic white females, Hispanic/Latina females and Asian/Pacific Islander females reported significantly less frequency of vigorous/moderate and strengthening/toning activities. There were no race/ethnic differences among males. Conclusions: These findings highlight the need to create targeted interventions for college men and women and among racial/ethnic subgroups.