Background: Anti-tuberculosis regimens had proven their high efficacy, but it requires a long duration of treatment and many drugs for cure. Poor adherence and default from treatment for tuberculosis could result in worsening of clinical manifestation, as well as emergence of drug-resistant tuberculosis and death. This study aimed to investigate the individual and clinical characteristics of defaulted patients, and to identify the risk factors associated with default from tuberculosis treatment. Methods: We performed a retrospective, case-control study analyzing 40 default cases and 80 control patients who were cured, completed or maintain treatment. We defined default as interrupting treatment for two or more consecutive months. We surveyed individual information using tele-research in default cases and personal interview in control patients, with assistance from public-private mix (PPM) nurses. We investigated clinical data on the basis of electronic medical records. Results: There was a trend towards default in patients with previous treatment (42.5% vs. 20.0%, p=0.009), shorter duration of previous treatment (5.18 months vs. 8.88 months, p=0.039), previous default (15.0% vs. 1.3%, p=0.005), and extrapulmonary tuberculosis combined (50.0% vs. 28.8%, p=0.022) or alone (35.0% vs. 3.8%, p＜0.001). Patients who were treated by pulmonologist as an attending physician (24.8% vs. 78.9%, p＜0.001) and had admission during intensive treatment phase (32.5% vs. 53.8%, p=0.028) were less defaulted. In multivariate analysis, pulmonologist as an attending physician (aOR 0.056, 95% CI 0.016 - 0.202, p＜0.001), history of previous treatment (aOR 3.437, 95% CI 1.232 - 9.589, p=0.018) might be the significant predictive factors associated with default from tuberculosis treatment. Conclusions: History of previous treatment could be risk factor for default from tuberculosis treatment. On the other hand, management by pulmonologist could be preventive factor.