A reverse phase liquid chromatographic (RP-LC) meth od was developed for the quantification of Idebenone and its related impurities in drug substa nce. The method was optimized in a Zorbax SB C 18 stationary phase for the separation of known impur ities with excellent detection limit in (i.e. less than 75 ng mL -1 ) the drug substance. A linear gradient elution was involved with the water-acetonitrile-trifluoroacetic acid as mobile p hase. The flow rate, wavelength was set as 1.0 mL min -1 and 215 nm respectively. The stability indicating c apability of the developed method was demonstrated using the stressed sample at hydro lysis, oxidative, thermal and photolytic conditions. The developed RP-LC method was validate d in compliance with ICH requirements. The developed method can be used for the determinat ion of synthetic and degradation impurities in the regular quality control analysis for the dru g substance.