We report a model for impedance Z(h) of oxygen transport in a PEMFC channel. Analytical solution for Z(h) is derived and a simple approximate equation for the summit frequency of Z(h) arc is obtained. In the limit of zero frequency of AC signal, a rather cumbersome expression for Z(h) reduces to a simple equation for the cell resistivity due to oxygen transport in the channel: R-h = -b (J(lambda - 1) 1n (1 - 1/lambda))(-1) - b/J, where b is the ORR Tafel slope per exponential basis, lambda is the stoichiometry of the oxygen (air) flow, and J is the mean current density in the cell. (c) The Author(s) 2019. Published by ECS.