A new sensitive, simple, rapid, and precise HPLC method with diode array detection has been developed for separation and simultaneous determination of hydrochlorothiazide, furosemide, torasemide, losartane, quinapril, valsartan, spironolactone, and canrenone in combined pharmaceutical dosage forms. The chromatographic analysis of the tested drugs was performed on an ACE C18, 100 Å, 250×4.6 mm, 5 μm particle size column with 0.0.05 M phosphate buffer (pH=3.00)-acetonitrile-methanol (30+20+50 v/v/v) mobile phase at a flow rate of 1.0 mL/min. The column was thermostatted at 25°C. UV detection was performed at 230 nm. Analysis time was 10 min. The elaborated method meets the acceptance criteria for specificity, linearity, sensitivity, accuracy, and precision. The proposed method was successfully applied for the determination of the studied drugs in the selected combined dosage forms.