A procedure for the controlled-potential coulometric (CPC) determination of ruthenium is proposed. The procedure is based on the redox reaction [Ru(CO)Cl5]2–/[Ru(CO)Cl4(H2O)]2– followed by the synthesis of the [Ru(CO)Cl5]2– depolarizing complex under microwave irradiation. The procedure was used in the analysis of a domestic commercial Ru(OH)Cl3 preparation.