Bone mineral content and soft tissue (lean and fat) mass in living female cynomolgus monkeys were successfully measured with a dual-energy X-ray absorptiometry (DEXA ; DPX-alpha, LUNARE, USA). Measurements were performed using a restraining bed made of forming polystyrol with 5cm thickness to support the animal in a supine position. Accuracy of measurements was checked by using a dummy consisted by various combinations of lean, lard and ribs. The results confirmed that this system is able to measure each consitituent exactly. The percentage of fat in the soft tissue is seemed to be better index of obesity in this primate species when compared with other obesity markers such as body weight and morphometry.