Abstract: Adult Schistosoma japonicum worms and Oncomelania hupensis hupensis tissue sections were employed as antigens in the studies of anti-O.h.hupensis rabbit serum and anti-S.japonicum adult worm rabbit serum by indirect immunaperoxidase assay.The result indicated that the most prominent peroxidase reaction was presented in the adult worm sections and the head-foot and liver sections of O.h,hupensis.These suggested the possible presence of antigenic homology between Schistosoma japonicum and Oncomelania hupensis hupensis.(Figs.1-7)