A methodology to determine dielectrical properties of human skin is presented and analyzed. In short, it is based on a mathematical model that considers the local transport of charge in the various layers of the skin, which is coupled with impedance measurements of both stripped and intact skin, an automated code generator, and an optimization algorithm. New resistivity and permittivity values for the stratum corneum soaked with physiological saline solution for 1 min and the viable skin beneath are obtained and expressed as easily accessible functions. The methodology can be extended to account for different electrode designs as well as more physical phenomena that are relevant to electrical impedance measurements of skin and their interpretation.