The association of knowledge of health risks, living arrangements, and perceived stress with health-risk behaviors was examined in a sample of college students included in the Health Promotion and Disease Prevention Supplement of the National Health Interview Survey. Regressions of each health-risk behavior (dependent variable) were performed on the predicted correlates. Although knowledge was not associated with participation in physical activity or smoking, the study found that students who knew more about the harmful effects of alcohol drank less, and those with greater knowledge of health risks practiced fewer risky behaviors. Students living independently were more likely to smoke, and those living in residence halls were less like to do so. Drinking, however, was more common among students living in residence halls or independently than among those living at home. Hall residents engaged in more group physical activity than other students did, but their physical activity was unrelated to health-risk behaviors. Stress was associated with smoking but not with other health practices. The findings suggest that smoking may be less influenced by health knowledge and more associated than drinking is with a response to stress. Drinking appears to be a social activity associated with living among peers and is potentially modifiable by increased knowledge about the effects of alcohol on health.