Cathodic reduction of hypochlorite anions during electrolysis of dilute solutions of NaCl can, according to Robertson, be decreased by placing an inert separator with sufficiently small pores at the cathode surface. This causes a strong suppression of convection in the solution layer at the cathode. The present work deals with the calculation of the flux of hypochlorite ions to the cathode for different thicknesses of the stagnant electrolyte layer at the cathode. The flux of ClO- ions decreases with increasing current density and thickness of the stagnant layer. The migration effect causes a decrease of the Aux of ClO- ions to the cathode by up to 50%, relative to their diffusion flux. The theoretical results are in good agreement with published experimental data.