The pathohistological findings of transbronchial lung biopsy (TBLB) were compared between Mycobacterium tuberculosis infection (group A) and Mycobacteria other than Mycobacterium tuberculosis (MOTT) infections (group B). The number of positive pathological findings in TBLB were 14 (70%) in group A and 2 (16%) in group B, respectively. Eleven cases (55%) in group A were positive for acid-fast bacilli in TBLB by Ziehl-Neelsen stain, and 3 cases of group A showed granulomatous lesion in TBLB. In pathohistological findings of group B, 2 cases (16%) were granulomatous lesion, 4 cases (33%) were fibrosis, and 3 cases (25%) were inflammatory changes. The pathohistological examination of TBLB was more useful for the diagnosis of pulmonary tuberculosis than for MOTT infection.