For many patients with damage to the central nervous system (CNS), execution of motor tasks is very difficult, sometimes impossible, even after early participation in an active rehabilitation program. Several investigators have recently proposed that mental practice could be used by these patients as a therapeutic tool to improve their performance of motor functions, yet very little empirical work addresses this issue directly. This article discusses the rationale for investigating mental practice as a means of promoting motor recovery in patients with a neurologic disorder. We first present evidence supporting the existence of a similarity between executed and imagined actions using data from psychophysical, neurophysiologic, and brain imaging studies. This parallel is then extended to the repetition of movements during physical and mental practice of a motor skill. Finally, a new model is proposed to emphasize the key role of motor imagery as an essential process of mental practice, and also to stimulate additional research on this type of training in the rehabilitation of patients with motor impairments of cerebral origin.