Abstract: Thirty five compounds of substituted-(4-amino-1-naphthylazo)benzenes and subtituted-4-(diethylaminoethylamino)-1-naphthylazobenzenes were prepared according to the procedure of Elslager et al. Similarly were prepared 5-(4-amino-1-naphthylazo)uracil and 5-4-(diethylaminoethylamino)-1-naphthylazouracil. Thirteen compounds exhibited chemoprophylatic and chemotherapeutic activity in mice against schistosomiasis japonica; among them 2-chloro-4-nitro-4-(diethylaminoethylamino)-1-naphthylazobenzene (compound 26) and 5-4-(diethylaminoethylamino)-1-naphthylazouracil (I_b) possessed higher chemotherapeutic activity; the rates of worm reduction were round 70%.