A reversed-phase high-performance liquid chromatographic method for the determination of idrapril in human and rat plasma and urine and in rat tissue homogenates is described. The method is based on the electrochemical detection of idrapril without prior derivatization. Sample preparation simply consists in deproteinization with acetonitrile for plasma and tissue homogenates and in passage through a Sep-Pak C18 cartridge for urine. The limit of quantification is 12.5 ng/ml for plasma, 125 ng/g for tissues and 2.5 micrograms/ml for urine. The method is suitable for monitoring idrapril plasma pharmacokinetics in humans and its tissue distribution and urinary excretion in rats.