Contralateral pneumothorax after pneumonectomy is potentially fatal. We experienced two cases of right pneumothorax after left pneumonectomy in which the patients had multiple bullae in the right lung. Case 1 involved a 49-year-old man with non-small-cell lung cancer (NSCLC) who underwent left pneumonectomy after induction chemoradiotherapy. Eleven months after surgery, he had pneumothorax and was treated with chest tube drainage and pleurodesis. He was discharged but died of recurrent pneumothorax 1 month later. Case 2 involved a 57-year-old man with NSCLC who had left pneumonectomy. Five months after surgery, he had pneumothorax and was treated with chest tube drainage. Because of prolonged air leak, ligation of the ruptured bulla was performed with a percutaneous cardiopulmonary support system on standby. No pneumothorax recurrence occurred for 2 years. Although management of pneumothorax after pneumonectomy is challenging, surgical intervention may be useful and necessary especially when there is high risk of recurrent pneumothorax.