Theoretical investigation of steady state heating processes during potentiostatic electrolysis of a metallic salt in binary and in three component electrolyte solutions is carried out for a cell consisting of two identical parallel electrodes. Analytical and numerical results are given for temperature distributions for electrochemical cells at different values of current densities. The peculiarities of the temperature distribution at currents close to the limiting diffusion-migration current are investigated. Theoretical analysis of the temperature distribution in the cell is based on an exact solution of the electrodiffusion problem described by the Nernst-Planck equations and an approximate solution of the stationary heat conduction equation containing a source term corresponding to Joule heat generation in an electrochemical cell.