The binding and axonal transport of six lectins were studied in the peripheral nervous system of adult mice by an immunocytochemical method. After injection into muscle and subcutaneous sites, lectins known to bind preferentially N-acetylglucosamine or mannose sugars were transported axonally to ventral horn and dorsal root ganglion neurons. Twelve to 96 hr postinjection, these lectins were bound at the injection site to neuromuscular junctions, muscle spindles, and cutaneous nerves. Lectins known to bind preferentially N- acetylgalactosamine or galactose sugars, by contrast, were transported only to dorsal root ganglion neurons. Except for Sophora japonica agglutinin, these lectins were bound at the injection site only to cutaneous nerves. These differences in axonal transport were seen also when the lectins were applied directly to the proximal end of a transected mixed nerve.