A 57-year-old man undergoing intravesical immunotherapy with BCG for transitional cell bladder carcinoma presented with dyspnea, fever, hypoxemia, and a diffuse micronodular pattern on chest radiograph. Transbronchial biopsy specimen revealed widespread noncaseating granulomas, and acid-fast bacilli were identified in sputum as well as in the biopsy tissue. The patient's condition responded promptly to antituberculous antibiotics given in conjunction with corticosteroids. Although no growth was evident on TB culture of the specimens, the presence of organisms indicates a probable infectious cause of the pulmonary disease process.