Аннотация:The authors propose a way of determining the solubility product (SP) of poorly soluble copper(II)salts by minimizing the functional discrepancy between experimental and calculated curves of precipitation potentiometric titration with a copper indicator electrode. The procedure is based on the solubility product being a parameter of the calculation curve, and the minimum of the discrepancy functional is observed in the immediate vicinity of the true SP value. The values of the solubility product of coppe(II) oxalate and tartrate in water at temperatures of 21–22°C are determined.