A case of vertical transmission of hepatitis B in an infant, born to a carrier mother HBeAg negative an anti Hbe positive, who developed and hyper-acute hepatitis, is presented. It was thought until quite recently, that perinatal hepatitis B was only transmitted by those HBsAg carrier mothers with positive HBeAg and negative anti Hbe. The infant here presented shows that all HBsAg carrier mothers are potential transmitters, and that all their newborns must have immunoprophylaxis. The current impression also confirms that, in the case of these children being infected, it does not follow that they will remain chronic carriers, as is so often seen when the mother is a positive HBeAg carrier.