The recent power add-on drive wheelchairs (PADWs) provide greater physical activity, are easier to transport, and may be an excellent alternative for the typical manual or electric wheelchairs. The development of in-wheel motor for a PADW is the principal issues. In this paper, design, implementation, and testing of the permanent magnet synchronous motor (PMSM) for a PADW are presented. To design output power and torque of the motor, the equation of motion has been investigated. The design parameters were calculated and the dimension and shape of the motor which was limited by the In-wheel mechanism of the PADW were done by applying FEM and optimal design technique. The prototype of the motor mentioned above was fabricated with precise machining and assembling. Then the motor tested on dynamometer and the measured results of the motor were verified by comparing the design results. The fabricated motor was 80 mm in length with a diameter of 110 mm and small enough to be attached the driving unit of the PADW.