In a preliminary study a group of hemiplegic patients have been assessed for return of arm function for periods up to 64 weeks after stroke. The assessment procedure employs a few simple and easily performed tests which take into account principles of the central nervous control of movement. The tests are highly repeatable and can be carried out by staff untrained in medicine or any form of physical therapy. Patients have been divided into two groups on the basis of the scores obtained in the tests at 16 weeks after stroke. The group scoring 80% or more are very likely subsequently to recover useful function of the arm and hand. The group of patients scoring less than 80% at 16 weeks after stroke are likely subsequently to recover limited arm movements and little hand movement. The preliminary results would suggest that the tasks provide a guide to prognosis and an indiction of the most suitable type of general physical therapy.