Twenty cases of hemothorax in newborns, including 4 of our own patients, are reviewed in detail. This unusual cause of acute respiratory distress within the neonatal period was observed in 14 males and 6 females. Most of the patients were fullterm newborns. As causal factors hemorrhagic disease of the newborn (vitamin K deficiency), disseminated intravascular coagulation, arteriovenous malformations and pleural/vascular rupture are considered. The time of occurrence of bleeding symptoms ranged from 1 to 28 days of life. Sixteen out of 20 patients survived without sequelae, but in 4 cases the outcome was lethal.