Hydrogen can be produced from Ethanol through many industrial processes which may involve electrolyte species in some cases. The thermodynamic phase behavior of electrolyte solutions is very important for the design of such processes. The Pitzer model, initially designed for aqueous electrolyte solutions, has been adapted to the case of electrolytes in mixed solvent solutions. This approach was applied for calculating activity coefficients of the electrolytes KCl, CsCl, NaCl and NaBr in water-ethanol mixtures at 25 degrees C. The Pitzer parameters have been evaluated for each salt in both aqueous and ethanol-water mixed solvent by minimizing the objective function using experimental data from literature. The values of the standard deviations show that the Pitzer model can be used successfully in modeling activity coefficients of the electrolytes studied in both aqueous and ethanol-water mixed solvent solutions. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.