Since the novel coronavirus outbreak (COVID-19) was identified for the first time in China during December, 2019. The world faces the COVID-19 epidemic including Thailand. The Royal Thai Government has announced an Emergency Decree on Public Administration in an Emergency Situation B.E. 2548 which had been effected from 26 March 2020 onwards. The Royal Thai Government Gazette published an announcement prohibiting any person throughout the Kingdom from leaving their residence between 10:00 PM and 4:00 AM starting on April 3, 2020. It may impact national tuberculosis program. The main objective of this study was to compare the TB treatment outcomes during pre-and post-COVID-19 outbreak. The secondary objectives were 1. To evaluate the number of TB diagnosis test during pre- and post-COVID-19 outbreak, 2. To compare TB case notification during pre- and post-COVID-19 outbreak, and 3. To compare TB treatment outcomes during pre and post COVID-19 outbreak. A cross-sectional study was conducted in this research by using the secondary data which TB patients were registered into the NTIP program. Comparing the data of the first cohort of the fiscal year 2019 and the first cohort of the fiscal year 2020 for the topic of TB treatment outcomes pre- and post- of the first wave of outbreaks in 2019 and 2020. TB diagnosis analysis we used the data of the two cohorts (second and third cohort of the fiscal year 2019) and the data of two cohorts (second and third cohort of the fiscal year 2020) representing pre-and post- of the first wave of outbreaks in 2019 and 2020. The results of this study showed that the number of all TB cases during pre- and post- of the first wave of COVID-19 outbreak in 2019 and 2020 were 40,544 and 40,848 cases, respectively with slightly increase but not statistically different (p= 0.275). The case notification number of new and relapse cases were 38,875 and 39,231 cases, respectively with an increase but not statistically different (p=1.00). Before and after the lockdown (between the same year between cohort Q2/2020 and 3/20), there were 21,358 and 17,873 cases, respectively, a decrease of -16.3%. The number of TB patients who diagnosed by AFB smear of 23,792 (61.2%) and 25,731 (65.6%) cases, respectively showed a statistically significant increase (p<0.001). In contrast, the number of TB patients who diagnosed by only Xpert MTB/RIF of 717 (1.8%) and 577 (1.5%) cases, respectively showed a statistically significant reduction (p<0.001). In addition, during pre- and post- of the first wave of outbreaks in 2019 and 2020, the number of patients diagnosed by both AFB and Xpert MTB/RIF (AFB smear is initiated test for TB diagnosis, if AFB negative was founded the Xpert MTB/RIF is done) wirh 8,838 (22.7%) and 6,808 (17.4%), respectively showed a statistically significant reduction (p<0.001). The number of TB patients without results were 5,528 (14.2%) and 6,115 (15.6%), respectively, a statistically significant increase (p<0.001). The TB treatment outcomes of new and relapse cases during pre-and post- of the first wave of COVID-19 outbreaks in 2019 and 2020 showed that the success rate were 80.8% and 86.4%, respectively. There was a statistically significant decrease (p<0.001). Transferred-out were 0.7% and 1.3% with a statistically significant increase (p<0.001). Lost-to-follow up rate were 4.3% and 3.7%, respectively with a statistically significant reduction (p<0.001). On-treatment rate accounted for 0.8% and 6.2% with a statistically significant increase (p<0.001). In summary, this study is the first national study that presented the evidence of impact of the Covid-19 outbreak situation to TB programmes and services. Case notification number among new and relapse cases during post of the first wave of COVID-19 outbreak was lower, especially lockdown period, but not statistically different. The number of diagnosis examinations by Xpert MTB/RIF was declined. Moreover, treatment success rate trended to reduction. In order to operate TB programme effectively during the COVID-19 epidemic, an intensive TB cases finding especially among the high risk groups, for examples; out-patients and the prisoners should be done as well as screen COVID-19 in the same time. The results of this study provided the useful information of the trend of case notification, TB diagnosis test and TB treatment outcomes for prepare the TB strategies for the next wave of COVID-19 outbreaks.