The behavior of interlayer water was studied in detail for graphite oxide [24-26]. By using neutron scattering, it has been shown [24] that, in the interlayer space, water may exist at high humidity in two forms: translational motion capable form and translational motion incapable one. The interlayer distance in graphite oxide was found [25] to abruptly change in the vicinity of freezing point. Talyzin et al. [25] have also established the presence of two types of water in the interlayer space of graphite oxide. The same conclusion was also reached by Zhu et al. [26] who investigated the thermal expansion of graphene layers and explained the negative thermal effect by reversible diffusion of free Abstract: Current-voltage characteristics of graphene oxide (GO) films were explored in water vapor as a function of water content in the film. The films can contain free and bound water. A decrease in current with time at a constant voltage is associated with the decrease in water content. Reduced GO (rGO) films exhibited proton and electron conductivity. For the proton conductivity E a = 0.9 eV, for the electron conductivity induced by thermolysis and chemical exposure E a = 1.15 eV. The rGO films is an example of mixed electron-proton conductivity when material conductivity can be regulated by external conditions. The field effect in a graphene oxide transistor for different conductivity types has been discovered and investigated. The possibility of accumulation and storage of electric charge in Nafion and GO films was demonstrated for the first time. The storage is governed by humidity of ambient environment. Charge accumulation occurs directly in Nafion or GO films.