In the past few years there has been a growing interest in environmentally clean renewable sources for hydrogen production. in this context new technologies have been developed for ethanol and glycerine reforming. Hydrogen production varies significantly according to the operating conditions such as pressure, temperature and feed reactants ratio. The thermodynamic analysis provides important knowledge about the effects of those variables on the process of ethanol and glycerine reforming. The present work was aimed at analyzing the thermodynamic steam reforming of ethanol and glycerine, using Gibbs free energy minimization using actual temperature and pressure data found in the literature. The nonlinear programming model was implemented in GAMS (R) and the CONOPT2 solver was used to solve the equations. The ideality in gaseous phase and the formation of solid carbon was considered. The methodology used reproduced the most relevant papers involving experimental studies and thermodynamic analysis. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.