Fifteen newborns referred to the University of Utah Neonatal Intensive Care Unit (NICU) between 1971 and 1974 had septicemia and bronchopneumonia caused by streptococci of Lancefield group B. Eight of these infants could not be distinguished from others with idiopathic respiratory distress syndrome. All eight died and at autopsy were found to have bronchopneumonia. At autopsy, five of the ten subjects had bilateral pleural effusions. Eight of these early onset infections were caused by type III strains, three by type II strains, and four by Ia strains. The three survivors were infected by Ia organisms; two of these patients received antimicrobial therapy within one hour of birth and the other was treated at 20 hours of age. Among the 12 patients who died, six received no antibiotics and five were treated 12 or more hours after delivery. Earlier recognition may lead to more efficacious therapy of this most fulminant infection of the newborn.