Objective: To review the epidemiology and clinical course of hepatitis C virus (HCV) infection, to examine current data on the vertical transmission of HCV to neonates, and to develop recommendations for intrapartum and postpartum follow-up of neonates born to HCV-infected mothers. Data Sources: The English-language medical literature from 1988 to 1996 was reviewed through MEDLINE. Methods of Study Selection: Case series evaluating vertical transmission of HCV infection in neonates, determined by HCV RNA testing, after delivery and breast-feeding were reviewed and summarized. Tabulation, Integration, and Results: Vertical transmission of HCV infection was examined with respect to maternal human immunodeficiency virus (HIV) status (as heterosexual transmission of HCV is enhanced in HIV-positive patients) and chronicity of HCV infection. Vertical transmission of HCV from HIV-negative mothers with chronic hepatitis C ranged from 0 to 18%. The risk of HCV vertical transmission from HIV-negative mothers with acute hepatitis C may be higher than that from mothers with chronic HCV infection. Vertical transmission of HCV was proportional to maternal HCV RNA levels; no transmission was noted in women without HCV RNA, whereas the greatest transmission was noted in women with HCV RNA greater than 1 million copies/mL. Vertical transmission of HCV from HIV-positive mothers with chronic hepatitis C ranged from 6 to 36%. In colostrum, HCV RNA was found to be present in low titers. No studies have documented transmission of HCV infection to infants via breast-feeding. Conclusion: Vertical transmission of HCV complicates up to 18% of pregnancies in HCV-positive, HIV-negative women and 6–36% in HCV-positive, HIV-positive women. The highest rates of vertical transmission of HCV were noted in women with high HCV RNA or concurrent HIV infection. Breast-feeding has not been associated with vertical transmission of HCV infection.