An accurate, highly sensitive, precise and reproducible isocratic RP-HPLC method was developed and subsequent validated for the simultaneous analysis of Hydrochlorthiazide and Eprosartan in bulk and tablet dosage forms. Method development was carried out on Agilent Eclipse XBD-C18 (5μm, 150mm × 4.6mm I.D.) column. The mobile phase was a mixture of buffer (20mM KH2PO4) and methanol in the ratio of 80:20 v/v. The flow rate was set at 1.0 ml/min and UV detection at 225nm. The retention time of Hydrochlorthiazide and Eprosartan were found to be 3.34 min and 4.75 min respectively. Validation parameters such as linearity, accuracy, precision, and robustness, limit of detection (LOD) and limit of quantification (LOQ) were evaluated for the method according to the International Conference on Harmonization (ICH) Q2 R1 guidelines. In the linearity study, the regression equations Hydrochlorthiazide and Eprosartan were found to be y=0.0123x + 0.0019 and y=0.0034x - 0.0163. Correlation coefficient was 0.9984 and 0.9989 for Hydrochlorthiazide and Eprosartan respectively. The proposed method was successfully applied for the quantification of bulk and active pharmaceutical present in tablet dosage form.