Stability testing of an active substance or finished product provide evidence as to the quality that it remains acceptable up to the stated period under storage condition as on label. With this objective a stability indicating high performance liquid chromatographic method has been established for analysis of Olmesartan medoxomil in the presence of degradation products. The drug was subjected to stress condition of hydrolysis, oxidation, photolysis, thermal degradation. Extensive degradation was found in acid medium and alkaline medium. Minimum degradation was found in thermal degradation while there was no degradation found in photolytic condition. Successful separation of a drug from degradation product formed under stress condition was achieved on C18 column using methanol: water (60:40, v/v), pH 3.75 adjusted with 10mM o-phosphoric acid mobile phase. Flow rate was 1 ml min-1and the detector was set at wavelength of 270 nm. The method was validated for linearity, range, precision, and accuracy, limit of quantification and limit of detection. Because method effectively separates the drug from their degradation products, it can be used as stability indicating method.