Antigens for the diagnosis of clonorchiasis have been isolated from the adult Clonorchis sinensis. Following extracttion with a phosphate-citrate buffer solution, ultrasonic disintegration, and defatting with a chloroform-methanol mixture, the antigens were fractionated in a Diethylaminoethyl-Sephadex (DEAE-Sephadex) A 50 column using sodium chloride eluates. The antigens were evaluated by carrying out both skin tests and stool examinations to determine their sensitivity, specificity and cross reaction. These DEAE fractionated antigens show less cross reaction than Melcher's antigen. DEAE fractions were protein(280mµ peak) and nucleoprotein (260mµ peak) as indicated by spectrophotometry.