A histochemical study was carried out on the glycoconjugates of the nasal mucosa of rat and guinea pig using conventional techniques and peroxidase-labelled lectins. Both the respiratory mucosa and neuroepithelium were studied. Sulphate and sialic acid groups were found in the mucous layer of the neuroepithelia, Bowman's glands and goblet cells. In contrast, the nasal glands did not possess these groups, and only a few showed neutral mucins. Carbohydrate residues were more numerous in the acini of the Jacobson glands. Thus, the nasal glands in the rat and guinea pig are probably of a serous type because of the scarcity of carbohydrate residues.