The interrelations between migratory Purkinje cells and radial glial processes were examined immunohistochemically and electron-microscopically in the fetal mouse cerebellum. Migratory Purkinje cells identified immunochemically with anti-spot 35 antibody were apposed to the presumed radial glial processes. Putative immature migratory Purkinje cells were apposed to the radial glial processes identified immunochemically with monoclonal antibody 1D11 or anti-tenascin antibody. Junctional specializations related to cell adhesion were observed at the sites of contact between the immature neurons and glial processes. Furthermore, coated vesicles and coated pits were noted in the contact region. These findings support the concept of contact guidance of migratory Purkinje cells by radial glial processes through cell adhesion, and also suggest the trophic interactions occurring at the region of contact.