Comprehensive analysis of combustion and emission characteristics of HCCI engine operating on alternative fuels, including methane, syngas, methane/hydrogen and methane/syngas blends is conducted on the basis of CFD simulation with the use of detailed reaction mechanism. It is shown that the replacement of methane to methane/hydrogen blend with 50% H-2 volume content makes it possible to increase the output energy during HCCI combustion and simultaneously to reduce the NO and CO emissions. The use of methane/syngas blend as a fuel also leads to an improvement of HCCI performance and to reducing the pollutant emissions, including the emission of CO2. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.