OBJECTIVE: To investigate the effect of functional electrical stimulation (FES) on the motor function of lower limb in hemiplegic patients with stroke or brain injury. METHOD: Fifty subjects (age, 56.66+/-9.85 years old; prevalence duration, 113.49+/-79.94 days after stroke or brain injury) were assigned randomly to 1 of 2 groups; the experimental group (n=25) received conventional rehabilitation with FES and the control group (n=25) received conventional rehabilitation without FES. FES was applied 20 minutes concomitant with rehabilitation, 5 days per week for 4 weeks. Outcome measurements included muscle strength, modified Ashworth scale, Brunnstrom stage, motricity index, 10 meter walking test (10 MWT), and circumference ratios of lower extremity (including thigh and calf). Subjects were evaluated before treatment and at 4 weeks after treatment. RESULTS: No significant differences were found in the baseline measurements. After 4 weeks of treatment, there was significant improvement in thigh circumference ratio and 10 MWT in the FES group, when compared with the control group (p<0.05). CONCLUSION: Twenty sessions of FES, applied to postacute stroke or brain injured patients plus conventional rehabilitation, improved their motor and walking ability.