The performances of patients with radiologically or surgically verified focal lesions on a test requiring the identification of unfamiliar faces were investigated. Nonaphasic patients with posterior right hemisphere lesions and aphasic patients with substantial impairment in language comprehension showed a notably high frequency of defect. The frequency of defective performance in nonaphasic patients with right anterior lesions was higher than normal but less than that of the previously mentioned groups. Nonaphasic patients with left hemisphere lesions and aphasic patients without substantial impairment in language comprehension performed on a level comparable with that of control subjects. It is concluded that the identification of unfamiliar faces is a bihemispheric process, possibly involving linguistic as well as visuoperceptive components.