Three cerebellums of chinchillas were taken for the investigation. The collected material was fixed in formalin, dehydrated in ethyl alcohol and embedded in paraffin blocks. Next, the blocks were cut in a transversal plane into 12-μm–thick slices. The slices were stained with cresyl violet and examined under a light microscope. One can distinguish three deep nuclei of chinchilla’s cerebellum: dentate nucleus (lateral, nucleus dentatus s. lateralis), interposed nucleus (nucleus interpositus), fastigial nucleus (medial, nucleus fastigii s. medialis). Nucleus interpositus located in the central part of cerebellar hemisphere’s white substance makes the longest cellular band. Nucleus medialis lies in the white substance of the vermis the nearest to the medial plane of the cerebellum. Nucleus lateralis of the cerebellum is a distinctly outlined cluster of cells located the most externally in relation to the remaining nuclei. The nuclei of the cerebellum in chinchilla are made up of multipolar cells, oval and of fusiform shape. The distinctly marked predominance of oval cells of the cerebellum’s nucleus lateralis is worthy noticing, whereas the following predominate in nucleus interpositus and nucleus medialis: small multipolar cells (20–30 μm) and of medium size (30–40 μm).