Thirteen fetuses from terminated pregnancies were collected. The age of gestation ranged from 20 to 32 weeks. Nine mothers of these fetuses were positive for HBsAg, 5 of them were also positive for HBeAg, HBV DNA. Four mothers were negative for HBsAg. DNA was extracted from fetal leukocytes, liver, heart, spleen, kidney, etc. HBV DNA was detected by dot hybridization. The results showed that HBV DNA was positive in leukocytes and liver of a fetus whose mother was positive for HBsAg, HBeAg. The liver HBV DNA of the fetus was about 23.1 kb by Southern blot. When digested by Hind II, it was about 3.2 kb 13.4 kb and 23.1 kb. So our data might serve as an evidence of transplacental transmission of HBV infection. Transplacental transmission seemed to be related to serum HBsAg, HBeAg, HBV DNA and leukocyte HBV DNA of mother.