Indacaterol (IND), 5-[2-[(5,6-Diethyl-2,3-dihydro-1H-inden-2-yl)amino]-1-hydroxyethyl]-8-hydroxyquinolin-2(1H)-one, is an active pharmaceutical ingredient (API) which is used to treat chronic obstructive pulmonary disease (COPD). We followed the International Council for Harmonization (ICH) guide lines to study the degradation behavior of IND under various stress conditions. Stressed degradation of the drug was performed under hydrolytic (alkaline, acidic and neutral), photolytic, oxidative and thermal conditions. Identification and characterization of IND and its forced degradation products (DPs) were demonstrated by using LC-HRMS and MS/MS method. A total of three DPs (DP1-DP3) were identified and characterized. The IND was found to be stable under photolytic, oxidative and thermal conditions, whereas it produced three DPs in acidic, basic and neutral hydrolytic stress conditions.