Measurements of anthropometry, body composition, aerobic capacity, and work efficiency during submaximal work were made on various occupational groups including the Ainu, residing on Hokkaido, the northernmost island of Japan. For the variables studied, no evidence was found for large intergroup differences among the resident populations of Hokkaido that could not be explained by differences in age or physical condition. The relatively small statured residents of Hokkaido appear comparable in aerobic capacity and work efficiency to other small statured people around the world.