We have produced monoclonal antibodies directed against defined amino acid sequences of rhodopsin by using peptides for hybridoma selection, rather than for immunization. Mice were immunized with rhodopsin, and hybridoma culture supernatants were assayed by ELISA to detect anti-rhodopsin antibodies. These antibodies were further tested by competition ELISA using synthetic peptides from the rhodopsin sequence in order to select antibodies with the desired amino acid sequence specificity. Site-specific monoclonal antibodies selected in this way have affinities for the protein which are typically higher than that of antibodies which have been generated against peptide-carrier conjugates as antigens.