The authors report a study carried out on a consecutive series of 184 placentas of immature or small-for-dates newborn for whom a concomitant examination of the umbilical cord was carried out, with the purpose of finding out whether there was infection of the cord which was defined expressly as a true umbilical blood-vessel infection. The 27 cases of infection which were found were classified using a method with 5 values of 0 to 5 given to two sections of the cord that were sectioned. The one was near the placenta, the other near the fetus. Then the findings were compared with the clinical picture of infection in the infant and with bacteriological tests carried out on the digestive tract and on the meconium. This comparison shows how reliable this examination was in prognosing the risk of neo-natal infection and it would appear in screening out neo-natal infection by adding raised values for infection in the cord.