In 1991, a novel robot named Manus I was introduced as a testbed to study the potential of using robots to assist in and quantify the neuro-rehabilitation of motor skills. Using impedance control methods to drive a 2 d.o.f. planar robot, Manus I proved an excellent fit for the rehabilitation of the upper arm and shoulder. This was especially true in the case of rehabilitation after stroke. Several clinical trials showed that therapy with Manus reduced recovery time and improved long term recovery after stroke. This successful testbed naturally led to the desire for additional hardware for the rehabilitation of other degrees of freedom. This thesis outlines the mechanical design of one of four new rehabilitation robots. Its focus is the mechanical design of a robot for wrist rehabilitation. The anthropometric background data, the design's functional requirements, the strategic design selection and the detailed design are presented.