Abstract: A study was carried out to evaluate the development of Schistosoma japonicum (Chinese mainland strain) in inbred and outbred mice.Male mice of four inbred strains (C57BL,ICR,615,Jin-Bai Ⅰ) and two outbred strains (Km-P,Km-S) were used.Cercariae were collected from many F1 laboratorybred and -infected Oncomelania hupensis hupensis.Both snails and schistosomes were originated from Anwei Province.Each mouse was exposed to 40 cercariae of the same pool,10 mice for each strain were used in each of the 10 experiments.Daily stool examination for schistosome eggs were started 33 days after infection,and after 6 weeks all mice were autopsied and their worm burden was recorded.Results obtained from the present study indicated that the six strains of mouse can be grouped into two categories based upon the worm burden.The first category included the C57BL,ICR and 615 inbred mice in which the worm burden was higher than that of the second category to which the inbred Jin-Bai Ⅰ as well as outbred Km-P and Km-S strains belong.No consistent differences were observed in the body size or in the size of gonads of adult worms at the age of 42 days in the six strains of mice.But more hermaphroditic malformation of adult worms was found in outbred strain mice in which 11 specimens were observed than in inbred C57BL and ICR strains,in which only 2 and 1 specimens were obtained respectively.