A new spectrophotometric method was developed for simultaneous determination of compounds with interfering spectra in binary mixtures without previous separation, showing significant advantages over the conventional methods regarding minimal data manipulation and applicability. The proposed method was applied for the determination of Propranolol hydrochloride and Hydrochlorothiazide in Tablets formulation, for determination of sampling wavelength, 10 μg/ml of each of PRO and HCT were scanned in 200-400 nm range and sampling wavelengths were 289 nm for PRO and 270 nm for HCT are selected for development and validation of simultaneous equation method. For this method linearity observed in the range of 10-50 μg/ml for PRP and 5-25 μg/ml for HCT, and in their pharmaceutical formulation with mean percentage recoveries 100.13� 0.86 and 100.07� 0.58, respectively. The method was validated according to ICH guidelines and can be applied for routine quality control testing.