For development of immunoassay of p,p-DDT (4,4-dichlorodiphenyl-2,2,2-trichloroethane), synthesized were five derivatives of DDT haptens (DDA, DDHP, DDCP, DDHH, DDHHAP) that had a similar structure with DDT but a different length of linkers. Among these hapten derivatives, DDA (2,2-Bis(4-chlorophenyl)acetic acid), DDHP (5,5-Bis(4-chlorophenyl)-5-hydroxypentanoic acid) and DDCP (5,5-Bis(4-chlorophenyl)-5-chloropentanoic acid) were conjugated with keyhole limpet hemocyanin for the use as immunogen. Fifteen clones of monoclonal antibodies were produced from hybridoma fused between mouse spleen cell and myeloma cell. DDHH (6,6-Bis(4-chlorophenyl)-6-hydroxyhexanoic acid) and DDHHAP (3-[6,6-Bis(4-chlorophenyl)-6-hydroxyhexanoylamino]propanoic acid) in addition to DDA, DDHP and DDCP were conjugated to ovalbumin and bovine serum albumin for the use of coating ligands. As a result of affinity screening for fifteen monoclonal antibodies to ten coating ligands, the affinities were greatly influenced by structural similarities between DDT and its haptens, and steric hindrance of carrier proteins. Therefore, antibody affinity should be considered as a dependent characteristics by various coating ligands which were a complex of hapten derivative and carrier protein. Also, a proper affinity between antibody and DDT coating ligand was required to obtain a good DDT does-response curve.