Tuberculosis is a chronic infectious disease caused by Mycobacterium tuberculosis. It typically affects the lungs (pulmonary tube) but, can affect other parts of the body as well (extra pulmonary tube). The study was aimed to investigate the determinants of time to drop out of treatment for TB patients. Secondary data was used from 375 TB patients of the selected health stations and hospitals at Buno-Bedele and Illu Aba Bora Zones. The response variable for this study was the survival time (Time to dropout the treatment among TB patients) measured in days and the covariates were gender of the patient, marital status, HIV co-infection, Phase of TB treatment, TB type, TB category, Previous TB history, HIV Co infection, Anemia and Physical inactivity. Descriptive statistics, Kaplan-Meier Estimation method, Semi-parametric survival models and parametric survival models were used for the analysis of time to TB treatment dropout dataset. From 375 patients who started TB treatments about 24.8% dropout and 75.2% censored at the end of the study and the median survival time of TB patients were 199 days. The Log-rank results showed that marital status, HIV co infection, Diabetic mellitus, Cancer and Anemia cases had significant difference between the survival experience at 5% level of significance, whose different levels have an impact in the survival time of TB patients; whereas Sex, Phase of TB treatment, TB type, TB category, previous TB status, co-morbidity, and physical inactive had not significant difference between the survival experience at 5% level of significance. Finally, the result of Cox-proportion hazard model showed that, age, HIV co-infection and Anemia had a significant effect on tuberculosis patients during the study period.