A simple, speedy, precise, and accurate, stability-indicating reversed phase high performance liquid chromatographic method was developed and validated for simultaneous (Vieordt’s method) determination of montelukast sodium (MTK) and fexofenadine hydrochloride (FXD). The sample injection volume was 20 μl and the quantification was attained by UV-VISIBLE detector at 248 nm. The chromatographic separation was achieved on X bridge C18, 250 × 4.6 mm, 5 μm particle column, using an isocratic mobile phase comprising of acetonitrile: buffer (10 mM potassium dihydrogen phosphate solutions): methanol of pH 4.5 and in the ratio of 50:30:20 v/v/v at a flow rate of 1.5 ml/ min. The retention times for montelukast sodium and fexofenadine hydrochloride were found to be 3.62 min and 7.43 min, respectively. The drugs were exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were analyzed by the suggested method. Validation of the method was done as per International Conference on Harmonization (ICH) guidelines. Linearity was established for montelukast sodium and fexofenadine hydrochloride in the range of 0.020-0.100 mg/ml and 0.016-0.064 mg/ml, respectively. The limits of detection were 0.04 μg/ml and 0.07 μg/ml, respectively and the LOQ value 0.11 μg/ml and 0.023 μg/ml, for montelukast sodium and fexofenadine hydrochloride respectively. The method was found to be specific and stability-indicating as no interfering peaks of degradants and excipients were perceived. The proposed method is hence suitable for use in quality-control laboratories for quantitative analysis of both the drugs bulk and in combination, since it is simple and fast with good accuracy and precision.