The rate of mass transfer for the electrodeposition of copper ions has been investigated under different rates of stirring. The reaction occurs on the fixed cathode of a cylindrical cell where the anode is the stirring device. The following correlation has been obtained, j′ = 0.0791 (Re)−30(D1/D2)−0.70, which holds also for other transfer processes in cylindrical cells. The peripheral velocity of the anode, V, was the measure of the rate of stirring. The mass transfer rate constant, k, is a function of V0·70. Figures for the effective diffusion layer under forced convection are also given. The temperature dependence of the rate constant follows an equation of the Arrhenius type. The apparent energy of activation is 4500 ± 250 cal/mole, independent of the rate of stirring.