Brucellosis not only a zoonotic disease , but also causes heavyeconomic losses in animal industry, that give the high importance ofits control which depend mainly on accurate serological diagnosis andvaccination.Among all serological tests that had been developed , cELISAcould overcome the problem of cross reaction that occurred from otherbacteria sharing identical epitope , beside being rapid and highlysensitive.IThis assay performed by using mono clonal antibody against Aand M epitopes from lipopolysaccharides of S 19 and Rev 1respectively , as serological responses following infection orvaccination directed predominantly against the lipopolysaccahrides.. The prepared lipopolysaccharides have been characterized by