Nafion(R) 117 membranes were investigated by measuring the impedance response of the Au/membrane/Au cell between 140 K and room temperature in the frequency range 10(-2) to 10(6) Hz. The conductance and its activation energy were obtained for membranes aged either in air or in water after different pretreatments. Two different water environments can be identified in the membrane, and a relationship between the water content and the conductance has been observed.