It is widely agreed that the right posterior parietal cortex has a preeminent role in visuospatial and orienting attention. A number of lines of evidence suggest that although orienting and the preparation of oculomotor responses are dissociable from each other, the two are intimately related. If this is true, then it should be possible to identify other attentional mechanisms tied to other response modalities. We used repetitive transcranial magnetic stimulation (rTMS) to demonstrate the existence of a distinct anterior parietal mechanism of motor attention. The critical area for motor attention is anterior to the one concerned with orienting, and it is lateralized to the left hemisphere in humans.