A robotic exercise device has been developed(MIT-MANUS)capable of providing therapy to the arm for patients with weakness due to stroke. The randomized trial will compare conventional care, planar robot intervention and an intervention of planar and vertical robot training among patients with chronic, stable deficits. We will evaluate motor outcomes, effectiveness, cost, patient satisfaction and quality of life. The study will determine the efficacy of upper extremity robot therapy compared to supervised self-administered exercise therapy in patients with deficits due to stroke.