Objective : The purpose of this study was to determine the effects of functional electrical stimulation(FES) on arm motor function in patients with chronic hemiplegia. Methods : Eighteen consecutive patients who had chronic hemiplegia over 12 months after a stroke attack were included. They received conventional rehabilitation treatment without FES for 4 weeks, and then undertook FES on a hemiplegic arm daily for 20 minutes a session, five days a week, for an additional 4 subsequent weeks. Four channels of FES worked sequentially for such motions as eating. The outcome was assessed using a manual muscle test for arm strength, dynamometer, and pinch gauge for grip and pinch power; the upper extremity subset of the Fugl-Meyer motor Assessment (FMA) for hand function; and CMS10 measuring system for motion analysis at baseline, after 4 weeks and then again after an additional 4 weeks of post-treatment. Results : In a conventional rehabilitation treatment session without FES, there were no significant changes on finger or arm strength, and FMA (p>.05). In the FES session, there was significant increasement of arm strength, finger strength, and motor function by FMA after 4 weeks of treatment (p<.05). Furthermore, motion analysis showed significantly improved movement qualities on most parameters of pronation-supination movement, hand tapping, and finger tapping motions after 4 weeks (p<.05). Conclusion : FES is an effective treatment method for arm motor function in patients with chronic hemiplegia over 12 months after a stroke attack.