Four patients underwent bronchoscopy to evaluate a cavitary lesion (one patient), pulmonic infiltrate (two patients), and a lingular mass (one patient). In all cases, an endobronchial obstruction was found. In three cases, forceps biopsy specimens revealed acid-fast bacilli, and all four cultures subsequently yielded only Mycobacterium kansasii. Three of the four patients had AIDS. Endobronchial obstruction has been reported for Mycobacterium tuberculosis and other atypical mycobacteria; however, we believe this to be the first reported series of M. kansasii presenting as an endobronchial obstruction. Unlike the endobronchial lesions seen with M. tuberculosis and other atypical Mycobacterium, the lesions seen with M. kansasii responded favorably to therapy.