The projections from the nuclei of the brain stem to the cerebellar nuclei were studied with the horse-radish peroxidase (HRP) retrograde transport method. The following nuclei in the brain stem were labelled with HRP;the inferior olivary nucleus, the lateral reticular nucleus, the nucleus reticularis tegmenti pontis, the pontine nuclei, the spinal trigeminal nucleus, the principal sensory trigeminal nucleus, the mesencephalic nucleus of trigeminal nerve, the spinal vestibular nucleus, the medial vestibular nucleus, the nucleus reticularis medullae .oblongatae pars ventralis, the nucleus reticularis gigantocellularis, the nucleus reticularis paramedianus, the raphe nucleus pontis, the raphe nucleus obscurus, the raphe nucleus magnus, the perihypoglossal nucleus, the locus caeruleus, the gracile nucleus, the cuneate nucleus, and the external cuneate nucleus.It was found that there are different patterns for the cerebellar nuclei to receive the afferent fibers from the brain stem. The number of the labelled nuclei of the brain stem projecting to the cerebellar lateral nucleus is similar to that projecting to the interpositate nucleus, while the number of the labelled brain stem nuclei projecting to the cerebellar fastigial nucleus is smaller than the above two. The topographic organization of the projections from the inferior olivary nucleus to the cerebellar nuclei was discussed.