Bioelectrical impedance analysis (BIA) is commonly used to measure the percentage of body fat (%BF), but its accuracy is controversial. In addition, the equations are specific to the group for which they were established. As far as we know, there is no study examining the accuracy of BIA in Japanese middle-aged and older people. We compared %BF assessed using BIA with that of dual-energy X-ray absorptiometry (DEXA) in 102 female and 51 male local residents aged 40 to 78 y. Simple correlation coefficients were 0.79 for females and 0.69 for males, which are statistically significant (p<0.001). However, BIA tended to overestimate %BF in the lower BF group and underestimate it in the BF higher group, and only 45.1% for female and 47.1% for male subjects were measured accurately, i.e., within 10% of the measurement by DEXA. This result suggests that this model of BIA is an alternative for estimating %BF in Japanese middle-aged and older people as well as when subjects are within a normal body fat range, but greater accuracy is needed for lean and overweight subjects.