We investigate the utilization of anode exhaust gas from high temperature fuel cells as gasification or reforming agent in Solid Oxide Fuel Cell (SOFC) and Molten Carbonate Fuel Cell (MCFC) power plants. The minimal anodic recirculation ratio is determined by two approaches: based on stoichiometric considerations and using detailed modeling of all process units. In the latter case, the risk of carbon formation and system heat integration are considered. The results indicate that the stoichiometric approach can be used as a shortcut method only for the SOFC systems due to good agreements with the detailed calculations. Furthermore, the mass integration concept is a feasible option for a wide variety of fuels in SOFC plants thanks to their relatively high operating temperatures. In MCFC systems, significantly higher recycle ratios are required to suppress carbon deposition which makes this concept unattractive. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.