Research indicates that mirror neurons are important for social cognition, including emotion processing. Emerging evidence, however, also reveals that emotional stimuli might be capable of modulating human mirror neuron system (MNS) activity. The current study used transcranial magnetic stimulation (TMS) to assess putative mirror neuron function following emotionally evocative images in twenty healthy adults. Participants observed videos of either a transitive hand action or a static hand while undergoing TMS of the primary motor cortex. In order to examine the effect of emotion on the MNS, each video was preceded by an image of either a positive, negative or neutral valence. MNS activity was found to be augmented by both the positive and negative (relative to neutral) stimuli, thus providing empirical support for a bi-directional link between emotion and the MNS, whereby both positively and negatively valenced stimuli are capable of facilitating mirror neuron activity. The potential adaptive significance of this finding is discussed.