BACKGROUND: In the management of patients whose primary chemotherapy has failed, careful assessment is essential. It is important to find out as accurate a chemotherapy history as possible. Preferably it should contain the drugs which has never used before. The purpose of present study is establishment of retreatment regimen for pulmonary tuberculosis. The present report concerns the results of retreatment of pulmonary tuberculosis patients treated at National Masan Tubersulosis Hospital. METHOD: Retrospective cohort study was made 104 drug-resistant pulmonary tuberculosis patients who were treated by five regimens between Jan. 1994 and Now. 1996. All the patients taken medicine for second anti-tuberculosis regimens for the first time. We separated the patients by three groups(Group l : OFX+PTA+CS+PAS+Aminoglycoside, Group ll : PZA+PTA+CS+PAS+Aminoglycoside, Group lll : PZA+OFX+PTA+PAS+Aminoglycoside). RESULTS: The age distribution was most frequent in fourth decade(36patients, 34.6%) and the mean age was 42.6 year. The sex distribution was most frequent in the males(81patients, 85.7%). There was 31 patients(29.8%) with combined diseaes, 18 patients with complication and 24 patients(27.9%) with family history. Primary chemotherapy regaimens were HERAZ(S or K) in 48 patients (46.2%), HER(S or K) in 41 patients (39.4%) and others in 15 patients(14.4%). Result of drug sensivivity test showed that the resistance to INH and RFP is in 68 patients(65.4%), RFP is in 12 patients(11.5%), INH s in 3 patients(2.9%) and all sensitive to INH and RFP is 3 patients(2.9%). The clinical symptoms on admission were coughing(89.4%), sputum(69.2%), dyspenea on exertion(37.5%), weight loss(33.7%) blood tinged sputum (15.4%) and otheres. The extent of disease on the radiograph was far-advanced in 73 patients (70.2%), moderate in 28 patients(26.9%) and minimal in 3 patients(2.8%). The side effects for drugs were gastrointestinal troubles in 31 patients(29.8%), arthralgai in 22 patients(21.2%), skin rash in 12 patients(11.5%) and others. The negative conversion rate on sputum AFB smear was 85.6%(87.5% in Group l, 80% in Group ll and 90.5% in Group lll). The average negative conversion time on sputum was 4 month(4.0 month in Group l, 4.6 month in Group ll and 3.0 month in Group III). CONCLUSION: In the retreatment of pulmonary tuberculosis, ofloxacin is useful drug for the patients who are not available to use PZA and combination of PZA and OFX can be use effectively substively substituting for CS.