Abstract Monoclonal antibodies against two olfactory mucosal proteins, one with affinity for anisole-like and the other for benzaldehyde-like compounds, were applied to mouse olfactory epithelium. Responses to three odorants (anisole, benzaldehyde and amyl acetate) were measured. Of 26 antibodies, three (12%) inhibited responses only to the odorant with affinity for the antigen, nine (35%) inhibited responses to all three odorants, and 14 (54%) were without effect. None reduced responses by as muas 50%. The data support the hypothesis that there is a class of related proteins in olfactory neuronal cell membranes that function as receptor molecules and that other mechanisms also mediate odorant stimulation.