Abstract: To produce carboxy-terminal specific antisera against glucagon was coupled mainly via its aminoterminal histidine to thyroglobulin,using the amino group reactive pentandiol at pH 7.0 for the conju gation procedure. After repeated immunization of guinea pigs and rabbits, the antisera were obtained. The titer of guinea pig antiserum against glucagon was 1: 3000—1: 35000 and affinity constant was 9.3×10~(10)—11.4×10~(10)l ·mol~(-1). There were no cross reaction with GIP, INS, C-peptide and gas trin. The titer of rabbit antiserum against glucagon was 1: 900—1: 9000 and affinity constant was 0.36 × 10~(10)—3.9 ×10~(10)·mol~(-1). There were no cross reaction with 1NS, C-peptide and gastrin. The cross reaction with G1P was 0.02%.