It has been proposed that homonymous quadrantanopic visual field loss that respects the horizontal meridian is a pathognomonic sign of extrastriate cortical disease. However, two patients with this sign are reported--one with a rare striate and the other with an extrastriatal lesion of the visual cortex. It is therefore hypothesized that a homonymous quadrantanopia respecting the horizontal meridian may indicate striate and/or extrastriate cortical disease.