Objective: The authors designed this study to determine if differences exist between male and female collegiate athletes' supplement use and behaviors to modify body appearance. Participants: Collegiate athletes who participated in this study were 241 females and 210 males, aged 17 to 28 years. Method: Participants completed a questionnaire about the average number of times each week they performed specific supplementing, exercise, or dietary behaviors. Results: The authors found differences associated with gender for 9 of the 18 behaviors. Specifically, 2 of these 9 behaviors were dietary, 1 was supplementary, 3 were physique concerns, and 3 involved personal motivation for weightlifting. Conclusion: Male athletes reported a higher drive for size, speed, and power, whereas female athletes were more concerned with body fat, more likely to restrict caloric intake, and more prone to consume weight loss supplements. No differences were found by gender regarding supplement use to increase body size. (Contains 2 tables.)