Objectives: To develop and refine a scale of motivational factors related to healthy weight achievement and maintenance and to examine differences by gender and weight status. Methods: A cross-sectional survey of 300 university students aged 18-24 years. Results: Factor analysis yielded 6 factors--Intrinsic (Cronbach's alpha = 0.73): affective motivation, self-efficacy/interest; Extrinsic (Cronbach's alpha = 0.68): social reward, peer pressure, lack of choice, and authority influence. Males and normal-weight students showed higher affective motivation and overall intrinsic motivation compared to females and overweight students, (P less than 0.001). Conclusion: Intrinsic motivational factors and gender differences should be considered in developing obesity prevention interventions in this age-group.