The body composition of 36 professional Sumo wrestlers and 39 collegiate male students were assessed densitometrically. The means of body weight, BMI and %fat for Sumo wrestlers were 117.1 kg, 36.5 and 26.2%, extraordinarily large compared with untrained men (p < 0.001). Results of the analysis of variance of divisions of Sumo wrestlers revealed significant differences in body weight, fat-free mass, fat mass, BMI, fat-free mass index (FFM/height2) and fat mass index (FM/height2). For the visual expression of the hierarchical differences of body composition, fat mass index and fat-free mass index of the wrestlers in various leagues were plotted on a body composition chart. Wrestlers in the Sekitori division had significantly larger fat-free mass index scores in comparison with wrestlers from the lower divisions who share a common area of the chart. The cut-off point of fat-free mass index which divided Sekitori wrestlers from other wrestlers is approximately 30 and this value may be one of the anthropometrical indications of whether or not a Sumo wrestler is destined to be successful.