A complexometric titration of copper with dithiooxamide is described, in which silver is used as the indicator electrode. In the range from 1 to 10 p.p.m., the standard deviation varied between 1.68 and 0.54%. For concentrations up to 40 p.p.m., the standard deviation is probably no greater than 1 to 1.5%. Concentrations of 1000 p.p.m. of iron, 400 p.p.m. of cobalt, and 400 p.p.m. of nickel do not interfere.When a glass reference electrode is used, the method is also applicable to the titration of silver and mercury(II) ions.IN THE survey work of this laboratory, a method which had reasonable speed, sensitivity, and good accuracy was needed for determining copper in relatively small concentrations.