The dissolution of cathodically polarized copper under various conditions is definitely measured. The process is most substantially affected by the concentration of dissolved oxygen, while the effect of hydrogen ions is small. Stirring the solution produces a noticeable effect at high cathodic potentials. On the surface of a copper electrode, two opposite processes proceed, namely, the ionization of copper and the deposition of copper ions. A technique for estimating the true rate of the anomalous copper dissolution when the deposition of the dissolution products is minimal is proposed. These dissolution rates of copper substantially exceed the values evaluated from the analysis of the working solution. The integral dissolution of copper is considered in terms of the chemical conjugation of the copper ionization and oxygen reduction. The hydrogen evolution is thought of as also probable.