Background: High school students involved in athletics may face additional stressors and engage in more problematic behaviors, such as drinking, dieting, and gambling, than non-athletes, especially as they near the end of their high school experience. Studies have, in general, found mixed results as to whether sports serve a protective factor or are a risk factor when it comes to a range of health behaviors. Method: This study evaluated 653 high school seniors who were admitted to a large, public, West Coast university, during the spring prior to college entrance, and compared 513 athletes to 140 non-athletes across a range of health behaviors. Results: Those involved in sports were found to drink more than those who were not and showed a trend for more gambling and dieting. Women athletes dieted significantly more than either male athletes or female non-athletes. Gender and ethnicity differences were found in health behaviors and were controlled for as covariates. Athletes were found to exercise more and spend less time playing video games and using the Internet. Conclusions: Athletic involvement is associated with increased incidence of some risky health behaviors while also being associated with decreased incidence of other problematic behaviors. Implications for understanding and designing prevention and intervention efforts are discussed. (Contains 1 table and 1 figure.)