Infants born to women who are asymptomatic hepatitis B surface antigen (HBsAg) carriers frequently acquire hepatitis B virus infection in infancy. The spectrum of disease in such affected infants includes mild transient acute hepatitis B, chronic active hepatitis with or without cirrhosis, chronic persistent hepatitis, chronic asymptomatic HBsAg carriage, and, rarely, fulminant fatal hepatitis B. Recently, the administration of hepatitis B immunoglobulin has been demonstrated to reduce the risk of infantile acquisition of hepatitis B virus; hepatitis B vaccine may also be preventive in this setting. Three young infants, aged 8 to 16 weeks, who died of acute fulminant hepatitis were studied. In each instance, the mother was found, retrospectively, to be asymptomatic but HBsAg positive. One of these mothers was hepatitis B e-antigen-negative but hepatitis B e-antibody positive. All three babies were HBsAg positive; two who were tested for hepatitis B core antibody were positive. These three fatalities serve to dramatize both the importance of HBs Ag screening of pregnant women, particularly those with demographic factors that place them at increased risk for HBsAg carriage, as well as the significance of effective immunoprophylaxis for hepatitis B in all offspring of women with HBsAg seropositivity.