A simple Reverse phase liquid chromatographic metho d has been developed and subsequently validated for estimation of lansoprazole in tablet dosage form. The separation was carried out using a mobile phase consisting of disodium hydroge n phosphate buffer of pH 3.0, and Acetonitrile in the ratio of 30: 70. The column use d was Phenomenex Luna C8, (5 μ , 250 mm × 4.6 mm id) with flow rate of 1.0 ml / min using UV detection at 285 nm. The described method was linear over a concentration range of 40-60 μ g/ml for the assay of Lansoprazole. The retention time of Lansoprazole was found to be 8.82 min. Results of analysis were validated statistically. The results of the study showed that the proposed RP-HPLC method is simple, rapid, precise and accurate, which is useful for th e routine determination of Lansoprazole in tablet dosage form and in its pharmaceutical dosage forms.