Separation of the lungs with a double-lumen endobronchial tube facilitates the surgical approach and protects the bronchial system from contamination by pus or blood from the operated lung. We report a case of a 49-year-old man who suffered a gram-negative pneumonia requiring mechanical ventilatory support and prolonged hospitalization after pulmonary resection. Contamination of the ventilated-dependent lung was documented intraoperatively. Current information on postoperative infectious complications and preventive measures are discussed.