During the period november 1988-december 1989 eight cases of early onset neonatal Listeria monocytogenes infection were registered in the 'Neonatal Intensive Care Unit' of the University Hospital in Leuven (Belgium). Before bacteriological proof was available, diagnosis could be made in 7 cases, based on a characteristic clinical picture: a maternal flu-like syndrome leading to preterm labour with intact membranes, meconium stained amniotic fluid, perinatal asphyxia and respiratory distress of the neonate. In 5 infants a maculopapulovesicular skin eruption was present. Laboratory findings were non-specific. An interesting finding was the predominance of monocytes in the endotracheal aspirate of infected infants. In 5 out of 8 patients meningitis and intraventricular hemorrhage were present; two of them died, three developed severe neurological sequelae.