OBJECTIVE: The aim of this study was to develop and validate two equations that best predict body composition of overweight and obese postmenopausal women. METHODS: Bioelectrical impedance analyses (BIAs) and anthropometric data such as circumferences and skinfolds were incorporated in the development of these two equations, respectively, while dual energy X-ray absorptiometry (DXA) was used as the reference method. A total number of 196 overweight and obese Greek postmenopausal women were used (131 subjects to develop the equations, and 65 to validate them). RESULTS: The BIA equation was: (FFM)=38.475+0.207xWt-0.092xRz/Ht(2)+0.291xXc/Ht(2) (R(2)=0.800, p<0.0001) and the anthropometry equation was FM=-31.913+0.333xGC+0.840xbody mass index (BMI)+0.064x(biceps+triceps skinfold) (R(2)=0.835, p<0.0001). Both equations were found to result in unbiased estimates. Regarding reliability, BIA equation was found to be more reliable compared to existing ones when applied to this population. Additionally, BIA equation was more reliable compared to the anthropometric equation (+/-3.12642kg vs. +/-5.2342kg limits of agreement, respectively). CONCLUSION: These conclude that the equations developed in the current study are more reliable than the existing ones in the literature, and could be applied for assessing body composition in clinical practice and research.