We tested in great detail face perception and face memory in four cases of prosopagnosia. Three of them showed deficits of face perception and/or of familiar faces memory. There was one prosopagnosic patient, however, who showed no abnormality in face perception and discrimination and could recall familiar faces. This case suggests that a form of prosopagnosia may exist, which is due to the disconnection between face perception and face memory. X-ray CT, MRI and PET studies revealed that two patients did not have damage of the left hemisphere, supporting the view that prosopagnosia can arise from unilateral right-sided lesion.