Successful permanent endobronchial closure of a serious postpneumonectomy bronchopleural fistula is reported in a patient with a delayed diagnosis of Mycobacterium fortuitum-cheloni infection. Increasing experience, improved plugging agents, and a review of the literature suggest that in selected patients, this procedure can avoid complex repeat operations and reverse life-threatening situations. Although atypical mycobacterial infections occur with infrequency, they are difficult to treat and may lead, as in this patient, to a misdiagnosis. Operations on granulomatous tissues are prone to heal poorly, thus inviting tissue breakdown and chronic fistulas.