The permeability of dental enamel membranes can be estimated by means of diffusion-measurements with radio-isotopes. Because of the low intrinsic permeability of these membranes, determination via this route generally takes two weeks. In this paper a much faster electrochemical method is presented, in which the real and imaginary part of the membrane impedance are measured at discrete intervals in the frequency range 10 Hz–300 kHz. From the parameters that describe these electrochemical data, some were found to correlate closely with the permeability of enamel as determined with radio-isotopes on the same enamel sample. From these results it was concluded that especiallyvmax, the frequency where the imaginary part of the membrane impedance is maximal, and Z1 at 100 Hz, the imaginary part of the membrane impedance at 100 Hz, are of practical value as predictor for the permeability of enamel.