Abstract: For the quantification of Diclofenac Sodium in Pharmaceuticals dosage form by using High Performance Liquid Chromatography (RP-HPLC). Chromatographic separation was obtained by using chromatographic conditions on a system for obtaining the results according to USP specifications. The retention time (RT) was 7.6 min per analysis with mobile phase acetonitrile 40% and solution A 60%. The symmetry of column was 15cm x 4.6 mm with packing 5-µm L1 with flow rate 1.5mL/min and wavelength detected on 280nm by using Photodiode array detector.