Zebrin II/aldolase C is expressed in a stereotyped array of parasagittal bands and transverse zones in the cerebellum of many animals including birds and mammals. Here, section and whole mount immunohistochemistry has been used to characterize the expression of zebrin II in the cerebellum of the adult guinea pig. Purkinje cells in the adult guinea pig express zebrin II immunoreactivity at three different levels of intensity-high, medium and low. This expression pattern reveals an arrangement of parasagittal bands that are symmetrical about the midline and reproducible between individuals. The expression of zebrin II divides the vermis into four transverse expression domains from rostral to caudal: an anterior zone consisting of one zebrin II-immunoreactive band at the midline and at least three symmetrical bands laterally; a central zone, in which broad zebrin II-positive bands are separated by narrow bands of zebrin II-negative Purkinje cells that disappear caudally to leave no overt compartmentation; a posterior zone consisting of alternating bands of zebrin II-positive and -negative Purkinje cells; and finally, a nodular zone in which nearly all Purkinje cells express zebrin II. In the anterior and posterior hemispheres, zebrin II is also expressed in a banded pattern. These rostrocaudal and mediolateral patterns of zebrin II expression are reminiscent of those in other mammals including rabbit, rat, and mouse, and suggest that there may be a fundamental compartmental organization of the cerebellum that is conserved in mammals.