Pregnant women infected with hepatitis B and C viruses pose a risk for infecting their newborn infants by vertical transmission. We studied 6,253 pregnant women aged 12-49 years for infection with hepatitis B (HBV) and C (HCV) viruses. Infection was diagnosed by measuring IgG antibodies against HBc, HBs, HBe, as well as IgM-HBc and HCV viral antigens with commercially available immunoassay kits. HBV infection was detected in 113 cases (1.8%), and prevalence was significantly higher (2.4%) in a group of women with a high-risk pregnancy who were attending a perinatology hospital than in healthy pregnant women (1.67%, p < 0.05). Infection with HBV was significantly higher in women older than 30 years old (p < 0.05). HBsAg was found in blood, colostrum and vaginal exudate of two pregnant women; HBsAg was detected in the gastric aspirate but not in the blood of the two newborn infants. HBeAg and IgM-HBc were not detected in any of the samples. DNA-HBV was detected in serum of seven women, and DNA-HBV was detected in the gastric aspirate of only one of the newborns. HCV infection was diagnosed in three out of 111 women with markers for HBV infection (2.7%), and in 6 out of 1,000 women without these markers (0.6%). Anti-HCV antibodies were found in the serum of six of their infants during up to six months of age. Infants were monitored for one year and none of them developed any sign of hepatic disease. These results suggest that special attention should be paid to women older than 30 years and with a high-risk pregnancy, as they are at a higher risk of HBV and HCV infections.