Abstract Objective To assess weight changes, exercise and diet behaviors among college students from the beginning of freshman year until the end of senior year. Design Longitudinal observational study. Setting Private university in St. Louis, Missouri. Participants College students (138 females, 66 males). Main Outcome Measures Weight and height were measured, body mass index (BMI) was calculated, and exercise and dietary behaviors were assessed by questionnaire. Analysis Changes in weight, BMI, exercise, and dietary patterns from the beginning of freshman year to the end of senior year. Results Females gained 1.7 ± 4.5 kg (3.75 ± 9.92 lb) [mean ± SD] from freshman to senior year, and males gained 4.2 ± 6.4 kg (9.26 ± 14.11 lb) (both P < .001). Weight changes were highly variable between students, however, ranging from −13.2 kg to +20.9 kg (−29.10 to +46.08 lb). Conclusions and Implications Weight gain was common but variable among college students. Importantly, exercise and dietary patterns did not meet the recommended guidelines for many college students, which may have long-term health implications.