We report five cases of congenital muscular dystrophy with central nervous system involvement of the Fukuyama type (FCMD) in which cerebral cortical dysplasia was not uniform even in the same brain. We have categorized the dysplasia into three major patterns, each with a predictable topography despite individual variations. Cerebellar micropolygyria was localized to the dorsal halves of each hemisphere. Aberrant fascicles of myelinated nerve fibers, closely associated with micropolygyria, were found in the subarachnoid space of the dorsal cerebellar surface in all but one case. We discuss the characteristics of the cortical dysplasia of FCMD, particularly in relation to that of Walker's lissencephaly, pathogenesis, and the relationship between lesions of the central nervous system and skeletal muscle.