A controlled trial of retraining of the sensory function of the hand was undertaken in hemiplegic patients after the period of spontaneous recovery. Twenty hemiplegic patients with sensory deficit in the hand, two or more years after stroke, received systematic retraining three times a week for six weeks. Sensation in the plegic hand was tested before and after this period in these patients and in 19 untreated control patients. The treated group showed large and significant gains on all sensory tests (P < 0.001), while no change occurred in the control group. It is concluded that somatosensory deficit can be alleviated even years after stroke and that rehabilitation for stroke patients should include sensory retraining for those with sensory deficit.