Re-expansion edema is a rare, potentially life-threatening complication of the drainage of a spontaneous pneumothorax. With early recognition and timely treatment, complete resolution can be achieved. Risk factors include rapid re-expansion of the lung, young patient age, and a large pneumothorax persisting longer than 24 hours. If these risk factors are present, the chest tube should be inserted without primary suction. Doing so allows the lung to re-expand more slowly and may prevent this severe complication.