The pseudo-first-order rate constants For ion exchange of partially silver ion exchanged Y zeolites (AgnNa56-nY) with sodium ions are determined from chronoamperometric studies of zeolite-modified electrodes in aqueous solution. In the case of AgnNa56-nY when n less than or equal to 5.9 the electrochemical reduction of intrazeolite Ag+ cations is controlled by an intracrystalline ion-exchange process rather than by counterdiffusion of exchanging cations through the interconnected supercage system of the zeolite. Herein the methodology for analysis of this situation is developed where the rate of the electrochemical reaction is equated with the velocity of the rate-limiting ion-exchange reaction. Good agreement between theory and experiment was observed. The pseudo-first-order rate constant for Ag+ exchange with Na+ is relatively insensitive to the concentration of sodium in the electrolyte solution, but decreases as the silver loading in the zeolite is increased up to 5.9 silver ions per unit cell. The data are consistent with electron transfer to silver ions occurring subsequent to the ion-exchange step, confirming once again that electron transfer occurs outside of the zeolite framework.