||The purpose of the investigation was to develop a simple, rapid and accurate RP-HPLC method to determine assay of Olmesartan, chlorthalidone And Cilnidipine in Bulk and Pharmaceutical Dosage Form. The chromatographic separation was performed on Kromosil 250 x 4.6 mm, 5µm. Eluents were monitored on PDA detector at a wavelength of 240 nm using a mixture Buffer: Acetonitrile: methanol (45:50:5v/v). The column temperature was maintained at 30°C. Validation parameters such as system suitability, linearity, precision, accuracy, specificity, limit of detection (LOD), limit of quantification (LOQ), Stability of sample and standard stock solutions and robustness were studied as reported in the ICH guidelines. The retention time for Olmesartan, chlorthalidone And Cilnidipine was 3.357 min, 2.838 min and 3.722min respectively. Assay method further evaluated for Olmesartan, chlorthalidone And Cilnidipine analysis at low concentration of analyte and found limit of detection is 0.03, 0.05 and 0.02 ppm respectively and limit of Quantitation is 0.08, 0.16 and 0.07 ppm respectively. The percentage recovery of Olmesartan, chlorthalidone And Cilnidipine was 100.70%, 100.34% and 100.47% respectively. The %RSD for Olmesartan, chlorthalidone And Cilnidipine was found to be less than 1.08%, 0.9% and 1.3% respectively. Linearity of Olmesartan chlorthalidone, and Cilnidipine performed from 25% to 150% and the R2 is 0.999, intercept and slope found to be y = 43191x + 562.0, y = 65434x + 1255 and y = 76821x + 1619 respectively. The method was fast, accurate, precise and sensitive hence it can be employed for routine quality control of Olmesartan, chlorthalidone And Cilnidipine containing drug in quality control laboratories and pharmaceutical industries.