PURPOSE: The purpose of this study was to investigate the effects of 5 weeks of basic military training on the physical fitness and blood biochemical factors in obese military recruits. METHODS: Forty-eight male recruits (20-25 years of age) were randomly assigned to the Control group and Exercise group. Both groups completed 5 weeks of basic military training. The Exercise group additionally performed a resistance exercise twice daily in the morning and afternoon (1-3 sets, 3 days per week) and power walking (60-80% HRmax, 30 minutes) four times weekly. Four body composition variables, physical fitness factors, serum lipid profiles, and obesity-related hormone levels were analyzed. RESULTS: Body weight, body fat ratio, body mass index, and waist circumference were significantly decreased in both groups between pre- and post-exercise tests (p<.01). However, no changes in these parameters were observed between the Control and Exercise groups. Twenty-meter shuttle running and maximal oxygen uptake were significantly increased post exercise (p<.001). Total cholesterol, triglyceride, and low-density lipoprotein levels were significantly decreased in both (Control and Exercise) post-exercise tests (p<.05). Leptin in both groups was significantly decreased; however, ghrelin showed a reverse pattern (p<.01). A significantly changed maximal oxygen uptake value via training was noted in both groups (p<.001). The time and interaction between the groups and the time were also significantly affected (p<.001). CONCLUSIONS: Our findings suggest that an additional exercise-training program with the basic military training plays an important role in improving military fitness and combat power.