This paper presents a novel approach to experimental and numerical investigations of the methane/steam reforming reaction process over a nickel/yttria-stabilized zirconia fine powder catalyst. Methane/steam reforming is primarily considered as a hydrogen production process for Solid Oxide Fuel Cells, and therefore its reaction kinetic was investigated experimentally and numerically. The present paper describes the innovative implementation of an orthogonal least squares (generalized least squares: GLS) algorithm for the calculation of the reaction kinetics involving precise information and the uncertainties of the obtained results. The GLS method was applied to evaluate the reaction rate and therefore fractional conversion of methane. An analysis of the mathematical model points out that the experimental inaccuracy could be reduced and allowed for the calculation of the most probable values of kinetic parameters and their uncertainties. The GLS method secures a higher accuracy of measured data and estimates the most probable value of all model parameters. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.