Some ot the factors governing the response time of the fluoride-selective and chloride-selective electrodes have been investigated. The results of E—t and conductance measurements indicate that dissolution and charge-transfer processes control the ion-seiective electrode kinetics. The temperature coefficients of the rate constants for dissolution of the chloride electrode membrane, determined by E—t curves and conductimetric measurements, are similar. The results, and the fact that the dissolution is a second-order process, indicate that surface processes play the predominant role in electrode kinetics near equilibrium.