The present work describes a simple, precise and accurate HPLC method for estimation of montelukast sodium in bulk and in tablet dosage form. Montelukast sodium is a selective and orally active leukotriene receptor antagonist that inhibits the cysteinyl leukotriene (CysLT1) receptor. The separation was achieved by using Waters symmetry shield RP-C8 column and acetonitrile: sodium di-hydrogen Phosphate dehydrate (pH 3.7) in proportion of 70:30 v/v as mobile phase, at a flow rate of 1.5 ml/min. Detection was carried out at 225 nm. The retention time of montelukast sodium was found to be 3.721 min. The limit of detection was found 0.1357 μg/ml and limit of quantification 0.4111 μg/ml. The accuracy and reliability of the proposed method was ascertained by evaluating various validation parameters like linearity (1-30 μg/ml), accuracy, precision, robustness and specificity according to ICH guidelines. The method was statistically validated and RSD was found to be less than 2% indicating high degree of accuracy and precision of the proposed HPLC method. Due to its simplicity, rapidness, high precision and accuracy, the proposed HPLC method may be used for determining Montelukast in bulk or in pharmaceutical dosage forms.