The purpose of this study was to assess physical activity levels and the relationships between activity and personal characteristics among a cohort of college students and to determine personal characteristics that predict activity. A sample of 1,700 undergraduates was mailed a survey that requested demographic information and assessed health behaviors including self-reported physical activity. Of the 1,575 successfully mailed, a total of 903 completed questionnaires were received--a response rate of 57.3%. Nearly half of the respondents indicated they "exercised or participated in sports activities for at least 20 minutes that made you sweat or breathe hard" on three or more of the preceding 7 days (VIG). Nearly three-fifths reported they "walked or biked for at least 30 minutes at a time" on 3 or more of the preceding 7 days (MOD). Those reporting VIG were more likely to be younger Caucasian males. Those reporting MOD were more likely to be younger Caucasian females. Gender, race, being an intercollegiate athlete, and belonging to a fraternity or sorority were predictors of VIG. Gender, age, race, and being an intercollegiate athlete were predictive of MOD. These results are in agreement with other studies on the correlates of physical activity among college students. This study was funded by the University of Kentucky Prevention Research Center. (Contains 2 tables.)