The purpose of this study was to examine the influence of autostretching and static stretching on range of motion (ROM) and running economy (RE) in long-distance runners. Twenty-two male distance runners were randomly assigned to an autostretching group (n=8), a static stretching group (n=7) and non-intervention control group (n=7). The experimental protocol was composed of interventions between treadmill runnings for RE. The interventions were either autostretching or static stretching, after the first treadmill running. The oxygen consumption (VO₂) as RE was measured at three steady-state running speeds (240m/min, 268m/min, and 295m/min). Goniometric measurements of hip flexion and ankle dorsiflexion ROM were taken immediately before and after each treadmill running for RE. The results showed that the autostoretching group had a significant decrease in VO₂ at 240m/min (p＜0.05), and at 268m/min (p＜0.05). On the other hand, the control group had a significant increase in VO₂ only at 295m/min (p＜0.05). At the same time, the autostretching group had significant improvements in ROM for hip flexion (p＜0.05) and ankle dorsiflexion (p＜0.05). The static stretching group had no significant changes in RE or ROM. The results of this experiment suggest that autostretching had a positive effect in improving RE in subjects of this study, and indicate the possibility that improved RE leads to the improvement of long-distance runners' performance.