A pedicled flap obtained by mobilizing the right lobe of the thymus was used to protect bronchial sutures in 29 consecutive patients undergoing a right pneumonectomy and in 4 additional patients. Fourteen patients had received preoperative chemotherapy with or without radiotherapy. The flap procedure was, in general, easy to do, required an average time of 20.4 minutes, and did not cause added operative morbidity. Postoperative magnetic resonance imaging, performed in 21 of the 29 patients who had pneumonectomy, showed a viable flap in every instance. One bronchopleural fistula occurred in a pneumonectomy patient after induction chemotherapy plus radiotherapy in a patient in the pneumonectomy group in whom adult respiratory distress syndrome developed postoperatively and who required prolonged mechanical ventilation.