Project GRAD (Graduate Ready for Activity Daily) was a randomized controlled study to teach university seniors behavioral skills necessary for increasing and/or maintaining physical activity habits in preparation for the transition to working adult roles after graduation. This study examines the secondary effects of this intervention on body image concerns among college-aged men and women. Three hundred thirty-eight undergraduates (54% female, M age = 24 years, SD = 1.95; M Body Mass Index = 24.26, SD = 4.0) were studied. The sample was 61% Anglo, 16% Latino, 16% Asian/Pacific Islander, 4% African American, and 3% Native American/Other. Body image concerns were assessed at pre- and posttreatment using 2 subscales of the Eating Disorder Inventory: Drive for Thinness and Body Dissatisfaction. Because the latter concentrates on body parts typically associated with female concerns (e.g., thighs, hips, buttocks), a parallel scale was developed to target body parts that may be of more concern to men (e.g., legs, shoulders, arms, stomach). Results indicated that compared to the control group, women in the intervention showed a significant increase in drive for thinness without any changes in body dissatisfaction. For men, there were no significant changes in drive for thinness or body dissatisfaction. These results suggest that physical activity interventions may have some negative consequences of increasing concerns about thinness in women. This negative effect occurred despite intervention content designed to prevent concern over eating, dieting, and the importance of weight. Health promotion studies should include assessments of potential negative side effects.