BACKGROUND: Isolated leukopenia is rare, but it has important clinical implications during antituberculosis treatment. Inadvertent discontinuation of short-course regimen drugs for fear of leukopenia inevitably will extend the duration of treatment, and the treatment completion rate will decrease completion of treatment will be delayed. However no guidelines concerning proper management for leukopenia during antituberculosis treatment have been presented. So we performed this Therefore, this study in order was performed to confirm whether or not it is possible to continue evaluate the possibility of continuing the same short-course regimen in case of the development of if a mild-to-moderate degree of isolated leukopenia was to develop during antituberculosis treatment. METHOD: Thirty-six patients who had been prescribed a short-course antituberculosis regimen between January 1997 and August 1999, had newly developed, mild-to-moderate degree, isolated leukopenia during medication, and who had continued the same drug regimen in spite of despite leukopenia were enrolled. One patient had been lost to was not available for the follow-up, so the remaining thirty-five (twenty-five prospectively and ten retrospectively) patients were analyzed. Patients who had other known causes of leukopenia were excluded. A mild-to-moderate degree of isolated leukopenia was arbitrarily defined as having a peripheral blood leukocyte count between 2,000 and 3,499 mm3 and no evidence of coexisting hematologic abnormalities. RESULTS: 1) All thirty-five patients could were able to complete short-course anti-tuberculosis treatment without complication or a further decrease of leukocytes count to less than 2,000/mm3 in spite of despite continuous treatment with the same regimen. 2) The mean duration from start of antitituberculosis medication to detection of leukopenia was 6465 days. 3) The mean leukocyte count was 5,0351,583/mm3 before treatment, and the its lowest count was 2,908390/mm3 during treatment. Leukopenia recovered after completion of treatment (4,2831,269/mm3). 4) The main component of leukopenia was a the decrease in neutrophil count ( 3,361 1,732 vs. 1,512 423 mm3, p<0.05). CONCLUSION: In a case of a For mild-to-moderate degree of isolated leukopenia (2,000/mm3 WBC < 3,500/mm3) developed (,) developing during short-course antituberculosis treatment, it is suggested that we can continue the short-course antituberculosis regimen may be continued without complications.