This study reviewed and analyzed the prevalence of university students' participation in physical activity at the level necessary to acquire health benefits. 19 primary studies (published 1985-2001) representing a total of 35,747 students (20,179 women and 15,568 men) from a total of 27 countries (Australia, Canada, China, Germany, Nigeria, United States, and 21 European countries) are described and the amount of activity identified within each study is analyzed in accordance with the American College of Sports Medicine (ACSM) guidelines for physical activity. With respect to these guidelines, more than one-half of university students in the United States and Canada are not active enough to gain health benefits. Internationally, the same is true, although Australian students appear to have the highest level of sufficient activity (at 60%). Women, and especially African-American women, are among the least active students, and students living off-campus are more active than those on-campus. Insufficient activity is a serious health concern among university students. Appropriate interventions and tools to measure ACSM-recommended physical activity are needed.