Recent work on electrode polarization effects in ionic conductors is discussed and extended. Contrary to a recent suggestion, analysis of the ac conduction and electrode processes occurring in such materials should involve effectively mobile charged species of both signs, not just a single mobile species. Special consideration of likely charge‐transfer reactions in solid materials such as &bgr;‐alumina with platinum electrodes leads to a new specific result for the Warburg impedance appropriate for such situations. The over‐all impedance of the system involves a very high parallel capacitance showing &ohgr;−mfrequency response, with 0.5≤m≤1.5, of the type very frequently found experimentally.