Reaction mechanism for steam reforming of toluene is proposed for La0.8Sr0.2Ni0.8Fe0.2O3 perovskite catalyst. The proposed mechanism was derived from various characterization results such as temperature-programmed desorption (TPD) and temperature-programmed surface reaction (TPSR) water, TPSR toluene, TPD O-2 and in situ DRIFT of toluene decomposition, and steam reforming of toluene. Five kinetic models were developed based on the proposed dual-site reaction mechanism using Langmuir-Hinshelwood approach. Subsequently, the parameters of the kinetic models were estimated by nonlinear least square regression. A good agreement was obtained between experimental and model predicted results for the rate determining step based on reaction between adsorbed aldehyde and adsorbed oxygen. The adsorbed aldehyde species is produced from the reaction between adsorbed C2H2 or CH2 and adsorbed oxygen while the adsorbed oxygen species can come from the oxygen from water activation, lattice oxygen species, and/or the redox property of some metals such as Fe. This shows that the adsorbed oxygen species plays important role in this reaction. (c) 2014 American Institute of Chemical Engineers AIChE J 60: 4190-4198, 2014