Four patients, two men 25 and 43 years old and two women 20 and 40 years old, had complete monocular temporal hemianopsias, suggesting that it may be a more common functional deficit than has been recognized. The initial symptoms were visual loss and headache, and eye pain also occurred. Correct diagnosis is possible if the absence of a relative afferent pupillary defect and the persistence of a hemianopsia on binocular testing are demonstrated.