Behavioral studies have employed various types of experiment to investigate the links between vision and proprioception, and there is a good deal of evidence to suggest that these two sensory modalities participate in visuomotor abilities. Neurophysiological studies have shown that activity in the primary motor cortex (MI) can be modulated either by illusory or imagined movements or by visual signals of hand movements. What remains to be resolved is whether the sole image of the hand is sufficient to elicit MI activation or if vision of the movement is necessary. Here we examined whether visual feedback from one hand can modulate the activity of the primary motor cortex, even when visual guidance of the hand is not necessary to perform the motor task. In our experimental setup, motor cortical activity was measured using the lateralized readiness potential (LRP), a cortical motor potential generated partially in MI, when subjects had to press a button with the right or left hand, which was either seen or not. We found that the LRP amplitude differed significantly between the two conditions, suggesting that visual feedback from the image of the hand is sufficient to modulate activity of MI. This may reflect the involvement of bimodal cells in the premotor cortex and their possible action on motor programming and/or execution.