BACKGROUND: Endobronchial tuberculosis is one of the serious complications of pulmonary tuberculosis. Without early diagnosis and proper treatment of endobronchial tuberculosis, bronchostenosis can leave and lead to the collapse of distal lung parenchyme, bronchiectasis, and secondary pneumonia accompanied with moderate to severe dyspnea, cough, hemoptysis, and localized wheezing. Therefore steroid therapy has been tried to prevent bronchostenosis. But the effect of steroid therapy on the endobronchial tuberculosis is not definite at present. We tried to elucidate the effect of steroid on the treatment of endobronchial tuberculosis for prevention of bronchoste- nosis. METHODS: We observed the initial and sequential bronchoscopic findings, pulmonary function tests and simple chest roentgenograms in 58 patients diagnosed as endobronchial tuberculosis and admitted to Chung-Ang university hospital from 1988 to 1992. The patients in nonsteroid group (n=39) were treated with anti-tuberculosis chemotherapy only and steroid group(n=17) with combined steroid therapy. Sequential bronchoscopic findings, pulmonary function tests, and chest roentgenograms were comparatively analyzed between the two groups. RESULTS: 1) The endobronchial tuberculosis was highly prevalent in young females especially in third decade. 2) Both actively caseating type and the stenotic type without fibrosis was the most common in the bronchoscopic classification. 3) The sequential bronchoscopic findings in steroid group 2 months after treatment showed no significant improvements compared with nonsteroid group. 4) There was no significant difference between the two groups in the sequential bronchoscopic improvements according to bronchoscopic types. 5) We did not find any significant difference in improvements on follow-up pulmonary function tests and simple chest roentgenograms between the two groups 2 month after treatment. 6) There was no significant adverse effect of steroid during the treatment. CONCLUSION: Combined steroid therapy provably would not influence outcome of the treatment of endobronchial tuberculosis.