Because of the current interest in the use of syngas in gas turbine applications, this article provides an overview of the fundamental combustion characteristics of H-2/CO mixtures, with emphasis on ignition and flame propagation at high pressures. Specifically, the effects of pressure on the fundamental combustion properties, including auto-ignition delays, forced ignition limits, and laminar flame speeds, are demonstrated and discussed through several recent high-pressure experiments. The controlling reactions in ignition and flame propagation are identified. Through comparison of the newly obtained high-pressure experimental data and the computational results based on existing kinetic models, discrepancies in the rate parameters for the sensitive reactions are also discussed.