Back ground: The discovery and development of novel medications requires a methodical strategy based on analysis. CGMP and FDA rules require the adoption of more sensitive and reproducible techniques of analysis. Analytical techniques are developed using the same or equivalent equipment. There are very few new HPLC methods that don't resemble or compared to present, literature based HPLC methods. Aim: To develop and validate a new, simple, rapid, precise, and accurate RP-HPLC method development and validation for an estimation of tolvaptan in bulk and tablet dosage form. Method: The HPLC separation was carried out by reverse phase chromatography on Symmetry C18 (150 x 4.6mm; 5μm) with a mobile phase consist of acetonitrile:methanol:buffer (680 mg potassium dihydrogen phosphate in 500 ml water, pH-3