A new, rapid, precise, selective and sensitive validative forced degradative UV spectroscopy method was developed for estimation of Montelukast sodium in bulk and pharmaceutical formulation in the developed method, the absorbance was measured at  272.19nm.the drugs obeyed the Beer’s law in the  concentration range of 30-150μg/mL. Accuracy studies of the method were determined by recovery studies and were found to be 99.9 for Montelukast sodium. It can be used for routine analysis of drug in bulk and in pharmaceutical formulation.