To investigate the age-specific prevalence of hepatitis B surface and e antigens (HBsAg and HBeAg) in pregnant women, we studied all the parturients encountered in National Taiwan University Hospital between 1985 and 1990. Serum HBsAg and HBeAg were checked by radioimmunoassay. The prevalence rate of HBsAg in pregnant women was 13.2%, 12.7%, 11.4%, 11.7%, 12.9% and 14.2%, respectively for each year. The figures seemed stable. The positive rate of HBeAg in HBsAg-positive pregnant women was 32.8%, 39.9%, 42.6%, 30.8%, 32.0% and 31.7%, respectively during the past 6 years. We also analyzed the results in different age-grouped pregnant women. The positive rate of HBsAg was 12.8%, 13.1%, 11.6% and 11.5% respectively in 21-25 year-old, 26-30 year-old, 31-35 year-old and 36-40 year-old groups. The positive rate of HBeAg in HBsAg-positive pregnant women was 49.4%, 36.5%, 31.5% and 20.0% respectively in these 4 age groups, with a prevalence declining with the advanced age. We conclude that HBsAg-positive rate was 11-14% in the pregnant women who visited our hospital, and their HBeAg-positive rate was 31-43%. No decrease of HBsAg carriage or HBeAg prevalence was seen in the past 6 years.