Chemical stability-indicating HPLC study of fixed-dose combination containing Metoprolol tartrate and Hydrochlorothiazide was developed and kinetic behavior of drugs was appointed and presented in respect of different pH (acid media with pH = 2.0, neutral media with pH = 7.4 and alkaline media with pH = 9.0) and time. The HPLC method was validated according to European Pharmacopoeia requirements and chromatographic and analytical parameters specificity, reproducibility, accuracy, LOD, LOQ and system suitability test were studied.