The authors reviewed studies on college students' physical activity (PA) behaviors and found that previous research on this topic focused on describing college students' PA patterns and their determinants. Researchers reported that about 40% to 50% of college students are physically inactive. More important, health and PA professionals in higher education have not been able to effectively increase students' PA behaviors. Interventions to promote students' PA are still at an early stage and have only produced moderate effects. The authors found primary problems with the current research on this topic to be 3-fold: (1) college students' PA has been seriously neglected as a research topic, (2) there is a lack of multiple-level approaches (ie, personal, psychosocial, and environmental levels) for examining PA behaviors in the college student population, and (3) measures of PA are subjective and inconsistent, which makes comparisons of PA patterns among different samples very difficult or impossible.