The objective of the current study was to develop a validated, specific and stability-indicating reverse phase HPLC method for the quantitative determination of Dronedarone and its related substances. The determination was done for active pharmaceutical ingredient and its pharmaceutical dosage forms in the presence of degradation products, and its process-related impurities. The drug was subjected to stress conditions of hydrolysis (acid and base), oxidation, photolysis and thermal degradation per International Conference on Harmonization (ICH) prescribed stress conditions to show the stability-indicating power of the method. Significant degradation was observed during acid, oxidative and photo stress studies. In the developed HPLC method, the resolution between Dronedarone and its process-related impurities was found to be greater than 2.0. Regression analysis shows an r value (correlation coefficient) of greater than 0.999 for Dronedarone and it's all the five impurities. The chromatographic separation was achieved on a C8 stationary phase. The method employed a linear gradient elution and the detection wavelength was set at 288 nm. The stress samples were assayed against a qualified reference standard and the mass balance was found to be close to 99.6%. The developed HPLC method was validated with respect to linearity, accuracy, precision and robustness.