The unaffected upper extremity of chronic stroke patients was restrained in a sling during waking hours for 14 days; on ten of those days, these patients were given six hours of practice in using the impaired upper extremity. An attention-comparison group received several procedures designed to focus attention on use of the impaired upper extremity. The restraint subjects improved on each of the laboratory measures of motor function used--in most cases markedly. Extensive improvement, from a multi-year plateau of greatly impaired motor function, was also noted for the restraint group in the life situation and these gains were maintained during a two-year period of follow-up. For the comparison group only one measure showed small to moderate improvement, and this was lost during the follow-up period; there was essentially no overlap between the individuals of the two groups. Thus, prolonged restraint of an unaffected upper extremity and practice of functional movements with the impaired limb proved to be an effective means of restoring substantial motor function in stroke patients with chronic motor impairment identified by the inclusion criteria of this project.