In this work, we analyze the i-E response of a redox mediator modified electrode in steady state and in the absence of permeation of the reactants into the film. We show that, besides some kinetic criteria existing in the literature based on the behavior of the limiting currents, there are others based on the entire i-E response. This analysis allows to explain several features of the i-E curve, yet unexplained, such as the shift of the half wave potential, electrochemical rectification, the shape of the Koutecky-Levich plots and the shape of the E vs. ln[(i(L) - i)/i] plots. From them, it is possible to determine, almost unmistakably, the type of kinetic control and to obtain the corresponding kinetic parameters. (C) 2007 Elsevier B.V. All rights reserved.