We examined pathologically 21 cases of multiple system atrophy (MSA). Density of Purkinje cell in 16 cases and of olivary nucleus cell in 20 cases was quantitatively measured, and their distribution as well as degree were studied. Contrary to the findings of previous reports, Purkinje cell loss was more pronounced in the vermis than in the hemispheres. Olivary nucleus cell loss was more outstanding in the accessory nucleus than in the inferior nucleus. A topographical characteristic of cell degeneration exists between the Purkinje layer and the olivary nucleus. Significant sparing of the nodulus apparently related to that of the vestibular system was found. While the common distribution of cell loss was seen, its degree varied considerably case by case. The degree was related to both duration of illness and, to some extent, clinical subtypes of MSA.