A differential morphometric analysis of the Purkinje cell (PC) population in 3 functional zones of the cerebellum was performed in 7 intact mongrel dogs of both sexes. The number of normal (light, dark, intermediate) and morphologically changed neurons was counted per 1 mm of the PC layer. It was shown that the medial, intermedial and lateral zones of the cerebellum did not differ in the number of dark and intermediate PC. The number of light PC in the medial zone was significantly less than in the intermedial and lateral ones. Consequently the difference also arose in the total PC number. It was discovered that PC distribution was not uniform either in the superior or inferior parts of cerebellum gyri. The morphological differences in the composition of the PC population of the medial, intermedial and lateral zones of the cerebellum are likely to reflect the functional inconsistency of these zones.