Two different methods were set up to detect the possible presence of lectin-like molecules with a specificity for mannose-rich glycans in the rat cerebellum. The first, affinity histochemistry, involved the isolation of a particular class of glycoproteins from the cerebella of 11-day-old rats followed by the formation of covalent complexes with horseradish peroxidase and then incubation with cerebellar slices. The second used in vitro interactions between [3H]leucine-labeled proteins, kept in solution, with insolubilized [14C]glucosamine-labeled glycoproteins. The results of both methods are compatible with the presence of lectin-like activities inhibited by high mannose concentrations, but not other sugars. However, the binding sites preferred by these molecules seem to be more than a single mannose residue.