The retrograde axonal transport of horseradish peroxidase (HRP) was used to study distribution of those Purkinje cells in the flocculus which project to the medial and superior vestibular nuclei of albino rabbits. HRP was injected electrophoretically into those nuclei and after survival for 24-48 h the flocculus was examined microscopically. It was found that Purkinje cells projecting to the medial nucleus were located relatively rostrally, while those projecting to the superior nucleus lay relatively caudally. These two groups of Purkinje cells, however, were distributed in such a way as to yield an interdigitated striped pattern over the surface of the flocculus.