We report the development and initial evaluation of a device for robotic assisted upper extremity repetitive therapy (RUPERT™). Intense repetitive physical therapies provided by individualized interaction between the patient and a rehabilitation specialist to overcome upper extremity impairment after stroke are beneficial, however, they are expensive and difficult to evaluate quantitatively and objectively. The need is urgent and growing for a low cost, safe and easy to use robotic device to assist the patient and the therapist to fully achieve the potential benefit of task-based repetitive physical therapies. We designed a pneumatic muscle (PM) driven therapeutic device, the RUPERT™, that is wearable and provides assistive forces required to move the arm during performance of several critical tasks of daily living. The robot has four degrees of freedom at shoulder, elbow and wrist. The sensors feedback position and force information for quantitative evaluation of task performance. It has the potential of providing a take-home method of supplementing therapy. The device can also provide real-time, objective assessment of functional improvement of therapy.