Pulmonary alveolar proteinosis is a rare disease of unknown etiology, characterized by progressive respiratory failure. Lung lavage has only been applied in a few children. A 6 month old boy suffering from severe pulmonary alveolar proteinosis was treated with three lung lavages. The first two were partial (or unilateral) lavages; a 3.5 mm flexible bronchoscope was introduced adjacent to a no. 3 cuffed endotracheal tube. This procedure allowed selective ventilation of one lung, and contralateral lung lavage. Respiratory improvement was observed during 1 week after the two procedures. At the third lavage we used partial veno-venous extracorporeal circulation because of severe respiratory failure. A significant improvement during the 5 following months was achieved. These results suggest that both partial and total lung lavage can be performed even in young infants and they may control the declining respiratory status in severe pulmonary alveolar proteinosis.