ABSTRACT.Maximum oxygen intake of 690 athletic and nonathletic Japanese adolescents were measured by a progressive treadmill exercise test. In the case of non‐athletes, the mean values of max &OV0312;2for boys increased with age and those for girls were almost constant from 12 to 18 years of age. There was a significant correlation (0.883 for boys and 0.597 for girls) between max &OV0312;2and body weight. The regression equations were calculated between them. Comparing nonathletes to athletes, there was a distinct difference in max &OV0312;2in 1/min and ml/kg.min.