Mucoid impaction presents a typical appearance on plain radiography and CT. If the lesion is multiple with manifestations of diffuse bronchopathy, it usually is a medical disease. On the other hand. if the lesion is single, an effort should be made to determine the underlying disease. The most frequent cause of the latter lesion is lung cancer, which generally can be depicted by CT. We retrospectively reviewed 13 cases of chest CT with obstructive mucoid impaction, in which CT and BFS(bronchofiberscopy) did not reveal a specific underlying cause. Women in the twenties and thirties were dominant and a past history of pulmonary tuberculosis was present in nine. BFS, done in nine, showed bronchial obstruction, and also luminal narrowing and cicatricial mucosal changes proximal to the obstruction in all of them. Endobronchial tuberculosis was proven in only one case by bronchial wall biopsy. Lobectomy was performed in three. The level of bronchial obstruction, determined by CT and BFS, was in the main bronchus in one, lobar bronchi in six, and divisional or segmental bronchi in seven. CT additionally showed calcific spots in their parenchyma connected to the bronchial obstruction in seven cases, and other changes suggestive of tuberculous origin in eight patients, In the context of the clinical history, BFS results, CT findings and pathologic findings of surgical specimen, most, if not all, of these 12 lesions are supposed to be a sequela of endobronchial tuberculosis.