AIM: It has been shown that body composition is determinant of health and mortality risk. Since body mass index (BMI) is not adequate measure of change in body fat mass and lean body mass, new indexes are proposed. However, reference values for specific populations are scarce. The purpose of this study is to determine fat free mass index (FFMI) and body fat mass index (BFMI) in healthy college students with low, normal, overweight, and obese BMI. METHODS: Lean body mass and mass of body fat were determined in healthy 672 male and female college students aged 18-22 years, by bioelectric impedance analysis. BMI, FFMI, BFMI and BFM/FFM were calculated. RESULTS: Results presented in the study indicate that men have lower values of BFMI and BFM/FFM, and higher values of FFMI than women within the same weight status category made by BMI. BMI correlates strongly to FFMI and BFMI in both women (rBMI-FFMI=0, 958, rBMI- BFMI=0, 985) and men (r rBMI-FFMI =0, 870, rBMI- BFMI =0, 924). There is significant strong correlation between BMI and BFM/FFM in men (r=0, 859) and in women (r=0, 945) CONCLUSION: BMI cannot by itself provide information on contribution of fat mass or fat free mass to body weight. Men and women with similar BMI differ significantly in FFMI and BFMI, indicating need for different reference values for sexes. There is significant strong correlation between BMI and FFMI and between BMI and BFMI in healthy young adults.