The day by day new combinations drugs are being launched in market. Then the multiple therapeutic agents which acts at diverse sites are used in the management of various diseases and disorders are done. Thus it is necessary to develop methods for analysis with the help of number of analytical methods which are available for the estimation of the drugs in combination. The analyst were estimate the rapid, selective, specific, simple, RP-HPLC method is developed and validated for simultaneous estimation of Losartan potassium and Hydrochlorthiazide in pharmaceutical tablet dosage form. RP-HPLC method was performed on the HPLC System with UV-VIS detector and Nucleodur,C8 (150 mm × 3.9 mm, 5 μm), using the mobile phase (Acetonitrile: Buffer B (7:93 v/v) pH 7.0 to 7.5 with 0.05% at a flow rate of 1.0 ml/min, injection volume 20 μl and UV detection at 280 nm. This method is validated according to BP, USP and ICH requirements for new methods, which include accuracy, precision, robustness, ruggedness, linearity and range. Linear relationships were obtained in the ranges of 100-300 μg/ml and 50-150 μg/ml with correlation coefficients of 0.9999 and 0.9996 at Rt value of 10.769 min and 21.633 min for Losartan potassium and hydrochlorthiazide respectively. According to ICH guidelines the developed method was validated. The proposed method can be used for estimation of these drugs in combined pharmaceutical dosage forms.