Abstract: In this paper, the trajectory planning of a two-link rehabilitation robot arm is addressed. Firstly, a Cartesian planning of the trajectory is defined to perform a proper motion exercise for the patient’s arm. Secondly, a trajectory planning in joint space is studied to obtain a similar Cartesian path with less computational complexity. The robot arm analyzed is the two degrees of freedom serial structure of the wire-based robot MariBot, which was designed and realized at the Robotics Laboratory of DIMEG (Department of Innovation in Mechanics and Management, University of Padua, Padua, Italy).