We examined the localization of the 140- and 180-kDa transmembrane isoforms of chicken N-CAM following transfection into mouse N2A neuroblastoma cells. Both isoforms were expressed at the cell surface and became partially or completely localized at areas of cell-cell contact after several days of culture or of in vitro differentiation. These results indicate that the presence of the large cytoplasmic domain of the 180-kDa N-CAM isoform is not necessary to bring about the localization of N-CAM to points of cell-cell contact.