An assessment inventory (the Friend/Peer Support-Health Eating Physical Activity Scale-FPS-HEPAS) was developed to measure social influence patterns of college student physical activity and food consumption habits. Principal components analysis of 50 items with two referent sets (friends and peers) produced two scales with common factors: encouragement to exercise, avoidance of high fat/salty foods, support for dieting and/or exercise to lose weight, and criticism about exercise behavior. The Friend Support scale also included a factor relating to criticism of eating foods high in fat or salt. The Peer Support scale included two subscales relating to exercising together and food intake to gain weight. Overall, females reported receiving greater support for their diet and exercise actions than did males. They reported getting more encouragement to exercise, practice good dietary habits, and watch their weight from friends and peers than did males. Gender differences in terms of composition of friends and peers also were found. Females received significantly higher levels of support for exercise, good dietary habits, weight loss, and higher criticisms about their exercise habits when their peer groups were at least half or mostly all male. By contrast, male students report their highest levels of support when their peers were mostly or all female. (Contains 7 tables.)