Introduction: Tuberculosis (TB) is among the top 10 leading causes of death globally. Association of Adverse Drug Reactions (ADRs) with Anti Tubercular Therapy (ATT) drugs has been encountered more commonly which causes significant morbidity and even mortality. Aim: To find out the predisposing factors and to assess the causality, severity and avoidability of the ADRs in proven TB patients treated under Directly Observed Treatment Shortcourse (DOTS) regimen. Materials and Methods: This study was conducted at the Department of Respiratory Medicine, King George’s Medical University, Lucknow. TB patients who were kept on DOTS regimen under Revised National Tuberculosis Control Programme (RNTCP), satisfying the inclusion and exclusion criteria with written informed consent, were recruited and monitored from May 2016 to April 2017. A total of 115 patients were enrolled for the study. TB diagnosis was confirmed by sputum smear. The treatment was initiated as per Category I-newly diagnosed patients of TB and Category II-previously treated patients pending drug sensitivity testing result (According to Treatment of TB: Guidelines, 4th edition, 2010, WHO, Geneva). The patients were followed up and monitored for suspected ADRs. For causality assessment Naranjo’s algorithm and WHO-UMC classification scales, for severity assessment Modified Hartwig and Siegel Scale according to severity levels, for avoidability assessment Halla’s scale were used. Categorical variables were presented in number and percentage (%). Chi-Square test/Fisher’s-exact test was used for the comparison of qualitative variables. The p-value of