Patients with limited focal frontal and nonfrontal lesions were tested for visual perspective taking and detecting deception. Frontal lobe lesions impaired the ability to infer mental states in others, with dissociation of performance within the frontal lobes. Lesions throughout the frontal lobe, with some suggestion of a more important role for the right frontal lobe, were associated with impaired visual perspective taking. Medial frontal lesions, particularly right ventral, impaired detection of deception. The former may require cognitive processes of the lateral and superior medial frontal regions, the latter affective connections of the ventral medial frontal with amygdala and other limbic regions.