The study was carried to investigate the change of hematocrit values on the loading of an approaimate submaximal motor intensity. The subjects of twenty college men, 10 athletes and 10 nonathletes, were tested for the packed cell volume of blood by the microhematocrit method The whole blood for each subject was obtained on the three experimental conaitions: 1) Pre load of the step tests, 2) Immediately after load requiring the step tests when pulse rate was approximatey 170 beats/Min., 3)At the reco very period when pulse rate was 100 beats/min. Through the experimental studies, the results were summarized as follow: 1. The Change of hematocrit values by liading fo submaximal moter inenity of the both of athletes and non-athletes was increased approximately 3 Per-cent. The result suggested that there was statistically significant deffernece on temporary increased of hematocrit value change, (P< 0.01). 2. There was no difference on the rate of hematocrit value increase between athletes and non-athletes by loading of submaximal motor intendity. The result showing non-significant difference on continuous increase of hematocrit. change. The null hypothesis that involving significant difference, therefore, was could be rejected with this study, (P >0.05).