This paper presents the main results from a research aiming at the design of an electromechanical actuator for use in the rehabilitation of ankle motor function in patients suffering due to neurological diseases. Motivations for the research project are discussed within the framework of the application of mechatronic concepts for rehabilitation practice. The entire design process is then described, from the definition of project targets through the mechanical concept and control design steps until design validation by means of numerical simulations and tests on a prototype.