The Polaroid pictures of computed tomographic examinations in 557 consecutive cases without visible temporal horns and 401 cases with temporal horns were examined. The most probable diagnosis of the patients are stated. Bilateral widening of the temporal horns was seen in cases with hydrocephalus of different causes. Widening of only one of the temporal horns was seen in cases with a unilateral mass, regional atrophy and of the temporal horn. Extremely small temporal horns may be visible on a normal examination.