Among 18 children of chronic HBsAg carrier Greek mothers, Papaevangelou and Hoofnagle1 found only three subjects with transiently HBsAg-positive cord blood and five others with evidence of HBV infection more than six months after birth and probably resulting from postnatal exposure. They therefore concluded that transplacental transmission of HBV infection is infrequent. The study of a similar series of 18 children of chronic HBsAg carrier Sicilian women followed with frequent controls for three to 14 months gave us different results.