Chemical kinetics in hydrogen combustion for elevated pressures have recently become more relevant because of the implementation of hydrogen as a fuel in future gas turbine combustion applications, such as IGCC or IRCC systems. The aim of this study is to identify a reaction mechanism that accurately represents H-2/O-2 kinetics over a large range of conditions, particularly at elevated pressures as present in a gas turbine combustor. Based on a literature review, six mechanisms of different research aroups have been selected for further comparisons within this study. Reactor calculations of ignition delay times show that the mechanisms of Li et al. and O Conaire et al. yield the best agreement with data from shock tube experiments at pressures up to 33 bar. The investigation of one-dimensional laminar hydrogen flames indicate that these two mechanisms also yield the best agreement with experimental data of laminar flame speed, particularly for elevated pressures. The present study suggests that the Li mechanism is best suited for the prediction of H-2/O-2 chemistry since it includes more up-to date data for the range of interest. (c) 2006 International Association for Hydrogen Energy.