Ureaplasma urealyticum was isolated in pure culture from blood tracheal aspirate and lung tissue in a newborn infant, who died of a severe pneumonia within 48 h after birth. The clinical course was characterized by persistent pulmonary hypertension of the newborn (PPHN). Post-mortem examination revealed extensive hyaline membrane formation combined with signs of inflammation in both lungs. The clinical and histopathological picture resembled that of early onset group B haemolytic streptococcal pneumonia/sepsis.