Can the body affect our morals? In the present study, we tested if motor system activation can change our moral decisions. Participants (N = 70) were presented with the choice to kill one person in order to save several lives. The action was described by means of hand (e.g., “push”) or foot (e.g., “kick”) verbs. As a secondary task, they moved rhythmically either their hands or their feet. Participants refused to act more often in both hand and foot dilemmas when they had been moving the same effector. We propose that the repetitive rhythm activates motor areas, leading to a more detailed simulation of the harmful act, so making more difficult the decision to carry it out. These findings reveal that mundane activities of the body can affect our most elevated decisions and suggest a causal implication of the motor system in moral cognition.