Reexpansion pulmonary edema[ RPE ] with hypoxemia and hypotension is a very rare complication of the treatment of lung collapse secondary to pneumothorax and pleural effusion. We experienced two cases of RPE. One is a 29 year old male with complete right pneumothorax and the other is a 20 year old female with massive right pleural effusion. Life threatening pulmonary edema was developed soon after insertion of chest tube in both. Fortunately, RPE was detected early and intensive treatment was performed. They were discharged without complication. Although RPE with hypoxemia and hypotension is rare , it is very serious and occasionally life-threatening. So, chest surgeon treating lung collapse must be aware of the possibility of RPE and make an effort to prevent the occurence of this condition.