Objective： To compare the accuracy of fat mass measurements between bioelectrical impedance analysis (BIA) referenced to dual-energy x-ray absorptiometry (DXA) measures. Methods： Fat mass were measured in 507 individuals： 213 men and 293 women with a mean age of 63.7 ± 10.8 years (range 28-89), body mass index 25.2 ± 3.5 kg/㎡ (range 14.7-39.8) using a InBody770 machine and Lunar Discovery machine. The fat mass values from each machine were compared with those from DXA under various conditions. Results： Mean fat mass were 23.0 ± 5.8 kg by DXA, and 21.3 ± 6.7 kg by BIA. The mean difference of fat mass between BIA and DXA was -1.7 ± 2.1 kg. Mean fasting glucose was 124.9 ± 38.2 mg/dL, mean HbAlc was 6.8 ±1.3 %, and 64.5% (n = 327) had diabetes. The BIA methods tended to underestimate the fat mass compared with DXA methods, especially when body mass index (BMI) was lower and waist circumference was lesser. The measurement of fat mass by BIA was calibrated for measurement of DXA. fat mass by using age and BMI. There were no significant differences of fat measurements between two machines by diabetes state or gender. Conclusion： BIA measurement of fat mass could be more accurately calibrated to DXA fat mass measurements by using age and BMI. Also, the differences in the measured values between BIA and DXA fat mass were not related to glucose metabolism.