Origin, course and distribution of the cerebellar arteries and of their branches are described. Anatomical drawings of the territory of these arteries are presented. They are based on a neuropathological study of 64 cases of cerebellar infarctions, the detailed study of which is reported elsewhere. The superior cerebellar artery (SCA) supplies a small brain stem territory, located on the dorsal tegmentum and the tectum of the upper part of the pons. The superior part of the cerebellum supplied by this artery includes the following lobules: lobulus anterior, lobulus simplex, lobulus semilunaris superior, and, in the vermis, lobulus centralis, culmen and clivus. The dentate nucleus belongs to this territory. The anterior inferior cerebellar artery (AICA) irrigates a ponto-cerebellar territory. It usually supplies the lateral territory of the lower part of the pons, the middle cerebellar peduncle, the flocculus and the neighbouring lobules of cerebellum. When the posterior inferior cerebellar artery (PICA) is hypoplastic, AICA takes over the territory usually supplied by the lateral branch of the PICA. The PICA always gives rami to the group of arteries supplying the dorsal medullary territory, but rarely participates to the supply of the lateral medullary territory. It supplies the lobulus semilunaris inferior, the lobulus gracilis, the lobulus biventer, the tonsilla cerebelli, and, in the vermis, the clivus, the tuber, the pyramis, the uvula and the nodulus. PICA never supplies the dentate nucleus. The flocculo-nodular lobe is usually supplied by 2 arteries: the flocculus is supplied by the AICA and the nodulus is supplied by the PICA.