In 100 patients with ocular skew deviation, the lesion was usually on the side of the lower eye, particularly when patients with internuclear ophthalmoplegia were excluded, but exceptions were sufficiently frequent to diminish the clinical lateralizing value of skew. Pontine damage was most commonly encountered, but midbrain-pretectal and medullary lesions were frequent. The onset of skew frequently coincided with acute brain stem damage, and while a wide variety of diseases produced skew deviation, stem strokes were present in more than two thirds of the patients. The hypothesis that skew results from damage to tonic otolith-ocular pathways is generally compatible with both the known anatomy of otolith pathways and the clinical presentation of skew. Otolith function testing in patients with skew, further anatomical definition of otolith-ocular pathways, and clinicopathological study of discrete lesions associated with skew should help resolve the causative role of the otolith organs in skew deviation.