We tested biological motion perception in a large group of unilateral stroke patients (N = 60). Both right and left hemisphere lesioned patients were significantly impaired compared with age-matched controls. Voxel-based lesion analyses revealed that lesions in superior temporal and premotor frontal areas had the greatest effect on biological motion perception. Moreover, the effect in each region was independent, and not attributable to indirect effects of lesions in the other area. When we explored functional magnetic resonance imaging (fMRI) data collected from neurologically healthy controls in a separate experiment in relation to the lesion maps, we found that the two methods converged on their findings. We thus establish that superior temporal and premotor areas are not only involved in biological motion perception, but also have causal relationships to deficits in biological motion perception. While the precise functional roles of each region remain to be identified, this network has been implicated in the perception of action stimuli in many studies and as such patients' deficits may reflect an inability to effectively engage the action observation system.