Abstract: The common antigen component between B. malayi and O. armillata was demonstra-ted by cross immunoelectrophoresis(XIE) with antigens from these 2 species of filariae against the sera from patients infected with B. malayt. When the two antigens were subjected to SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and enzyme linked im-munoblotting (ELIB), the component of approximately 43 KD was identified to be the common antigen component.