We propose an easy method for determining the diffusion coefficients of electrode reaction products by double potential step chronoamperometry at small disk electrodes. The necessary theoretical relationship between current and time for this method was obtained by digital simulation of a hopscotch algorithm. We quantified the digital results and showed the routine of the measurement. The method was verified successfully by an experiment in which the diffusion coefficients of both the elements of the [Fe(CN)(6)](4) -/[Fe(CN)(6)](3) - redox couple were determined by the usual potential step chronoamperometry and by this method.