A stability indicating LC method was developed for the simultaneous determination of Candesartan Cilexetil and Hydrochlorothiazide in pharmaceutical dosage form. Efficient chromatog. separation was achieved on Zorbax SB Ph (4.6 X 250 mm), 3.5 μ or equivalent stationary phase with simple combination of a mobile phase-A containing Buffer: 1000 mL of deionised water mixed with 1.0 mL of Methane sulfonic acid and mobile Phase-B as Acetonitrile delivered in an Gradient mode and quantification was carried out using UV detection at 210 nm at a flow rate of 1.0 mL min-1 with injection volume of 10 μl and column temperature as 40°c. This method is capable to detect both the drug components of candesartan Cilexetil and Hydrochlorothiazide in presence of their degradation products (Candesartan Impurity-1, 2, 3, 4, 5 & 6 and Hydrochlorothiazide Impurity-A) with detection level of 0.05 %. Candesartan Cilexetil and Hydrochlorothiazide in their combination drug product were exposed to thermal, photolytic, hydrolytic and oxidative stress conditions, and the samples were analyzed. Peak homogeneity data of Candesartan Cilexetil and Hydrochlorothiazide is obtained using PDA detector, in the stressed sample chromatograms, demonstrating the specificity. The method shows excellent linearity over a range of 0.05-2.0% and 0.05-1.5 % for Candesartan Cilexetil and Hydrochlorothiazide impurities: Candesartan Impurity-1, 2, 3, 4, 5 & 6 and Hydrochlorothiazide Impurity-1. The correlation coefficient for Candesartan Cilexetil and Hydrochlorothiazide is 0.9999. The relative standard deviation was always less than 2%. The proposed method was found to be suitable and accurate for quant. determination and the stability study of Candesartan Cilexetil and Hydrochlorothiazide in pharmaceutical preparations The developed HPLC method was validated with respect to linearity, range, accuracy, precision and robustness.