The fuel processor and a proton exchange membrane fuel cell (PEMFC) integrated process fueled by cassava based bio-ethanol and methane as co-reactant is theoretically investigated and compared with that run by dehydrated bio-ethanol in this work. The methane is added to bio-ethanol reformer as co-reactant to reduce dilution effect of crude bio-ethanol and adjust very high steam to carbon ratio of this system. The hydrogen fraction increases with the reformer temperature and methane to bio-ethanol ratio until reaching a maximum point. In addition, the optimal operating conditions of mixed bio-ethanol and methane reformer and dehydrated bio-ethanol reformer, which achieve the highest reformer efficiency, are presented. The results show that superior fuel processor efficiency, fuel cell efficiency and system efficiency are obtained when the mixed bio-ethanol and methane is used to generate hydrogen. The mixed bio-ethanol and methane reforming integrated with PEMFC system has the lower environmental impact, compared to the dehydrated bio-ethanol reforming integrated with PEMFC system. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.