Objectives: To investigate the effects of exercise advertising on self-efficacy and decisional balance for changing exercise behavior. Methods: One hundred seventy-four university students (females = 108; males = 66) watched a video that contained health, appearance, or control advertising and completed stage of change, exercise self-efficacy, and decisional balance questionnaires. Results: There was a significant condition by gender interaction indicating that men in the appearance condition had lower self-efficacy than did females. Health promotion advertising did not have any effect. Conclusions: This study provides evidence that the message in appearance-based advertising that men should be muscular may be detrimental.