Abstract: Females macaques were administrated single doses of 1,2, 4μg/kg TCDD(n=4 per dose group)on gestational day(GD)12. The controls(n=7)received the same dosing volume of acetonecoin oil.The results showed that poor appetite,weight loss,alopecia,dermatitis,anemia and other toxic reactions were recorded since rtrteatment day 10,and early fetal loss occurred between GDs 22 and 32 in 10 of the 12 animals treated,with TCDD.The results demonstrated that toxicity was induced by low level TCDD in pregnant macaques and pregnancy outcomes were affected too.