In this study, we examined the effects of static stretching (SST) for different durations on muscle oxygen saturation (StO2) and muscle blood flow (BFmus) in the stretched muscles during and after SST. Nine healthy male subjects received passive SST of the wrist flexors. SST was performed for 10, 30, and 60 s. The StO2 and BFmus in the forearm flexor muscles were measured by near-infrared spectroscopy. BFmus was determined from the rate of increase in total hemoglobin during venous occlusion. StO2 decreased immediately at the start of stretching, and thereafter kept decreasing until the end of SST. StO2 replenished rapidly after completion of SST and remained above the resting level during the recovery period. For all 3 durations of SST, the peak value of StO2 during the recovery period after SST showed a significant increase above the resting value (p<0.01) (10-s SST: 72.5±2.8%, 30-s SST: 72.5±1.8%, 60-s SST: 73.0±2.2%). There was no significant difference in the increase in the peak values of StO2 after SST among the 3 SST durations. For all durations of SST, BFmus after SST increased significantly above the resting level (p<0.01) (10-s SST: 2.6±1.2 fold, 30-s SST: 2.8±1.6 fold, 60-s SST: 2.9±1.0 fold), but there was no significant difference in the increase of BFmus after SST among the 3 SST durations. These results show that SST of wrist flexors for 10 s, 30 s, and 60 s induced an increase in StO2 and BFmus after SST, but the increase in StO2 and BFmus was not affected by SST duration.