A simple, sensitive and precise reverse phase high performance liquid chromatographic method has been developed for the simultaneous estimation of Irbesartan and Hydrochlorothiazide in pharmaceutical dosage forms. The mobile phase consisted of Acetonitrile: Methanol:Triethyamine (0.02 %) (0.1% v/v ortho phosphoric acid, PH 6) in the ratio of 30:15:55 v/v/v delivered at a flow rate of 1.0 ml / min and wavelength of detection at 274 nm. The retention times of Irbesartan and Hydrochlorothiazide were 5.903 min and 7.040 min respectively. The developed method was validated according to ICH guidelines. The proposed method can be used for determination of these drugs in combined dosage forms.