The purpose of this study was to investigate the effects on body composition and physical strength of inactive college students by implementing a 12-week complex exercise program targeting college students who are low in physical activity and do not exercise regularly. The subjects of the study were 25 students who were selected as inactive college students among those taking liberal arts and physical education courses at S University in Seoul. The main conclusions drawn from the research results are as follows. First, participation in a 12-week exercise program was found to have a significant effect on the body composition of inactive college students by reducing body weight, body fat, and both systolic and diastolic blood pressure. Second, the impact of participating in a 12-week exercise program on the physical strength of inactive college students was found to have a positive effect, with significant increases in muscle strength, muscular endurance, cardiorespiratory endurance, and agility. However, agility did not show significant results, and flexibility actually decreased and also showed no significant change. In conclusion, it was shown that a 12-week complex exercise program had a positive effect on body composition and physical strength in inactive college students, and further development of flexibility exercise programs and various complex exercise programs should be developed.