Objective: A study on incidence of adverse drug reaction of anti-tubercular drugs in new cases of pulmonary tuberculosis. Method: It was prospective observational study conducted on Positive pulmonary tuberculosis patients admitted in the ward of T.B and chest and enrolled on the directly observed treatment short course (DOTS) and monitored for ADRs. The causality and severity of adverse drug reaction carried out as per Naranjo scale and modified Hartwig and Siegel scale respectively. Result: In this study, Out of 263 patient enrolled on DOTS therapy, n= 74(28.14%) patients developed ADRs in which male patient were n= 48 (27.58%) and female patient were n= 26 (29.21%). Total no. of ADRs reported in n=74 patients were n=212. The severity of ADRs were from mild group with n= 161(75.94%) followed by moderate with n= 38(17.92%) and severe n= 13(6.14%). The causality of ADRs reported were probable with n= 158(74.52%) of cases, followed by possible n= 42(19.81%) and definite n=12(5.67%). The most commonly reported ADR was hyperacidity n= 34 (16.03%). Conclusion: This prospective study conclude that the majority of adverse drug reaction found during the treatment of pulmonary tuberculosis were mild with 75.94% and did not need modification of treatment or administration of specific antidotes followed by moderate with 17.92%, which required discontinuation or change of treatment and antidotes also required and Severe ADRs constituted 6.14% patients which requires intensive medical care.