During a large neuropathological survey of clinically normal sheep for evidence of scrapie, three adult Romney ewes from the same farm were found to have populations of distended neurons containing granular eosinophilic storage material. The affected neurons were confined to the striatum. The granules had the tinctorial properties of glycolipid and the ultrastructural appearance of spherical bodies containing concentric membranous whorls. The bodies resembled those of GM1 gangliosidosis. The restricted neuroanatomical distribution of changes together with the age of the sheep suggests a similarity to human type 3 GM1 gangliosidosis, which has not previously been reported in animals.