Transport properties of the plasticized polyvinylchloride membranes on the basis of tetradecylammonium associates with complex connections silver (I) – cefotaxime in the conditions of a diffusive mass transfer and a direct current are investigated. With variation of concentration of electrode active substances (0.5; 1; 2; 3%), the external solutions contacting with membranes (10-2–10-7 M). It is established that resistance of membranes depends on the content of electrode active substances (EAS) and concentration of perimembrane solutions of a cefotaxime.