The catalytic partial oxidation of methane (CPOM) to synthesis gas in a circulating fluidized-bed catalytic reactor has been simulated. Results of the simulation indicate that the equilibrium conversion of methane (approximately 93% at a riser pressure of 1 atm) may be achieved in a riser operating at an average solids holdup of 10%. The methane conversion drops with increasing pressure to less than 60% when the riser pressure is 10 atm. Addition of carbon dioxide to the feed was found to increase methane conversion. However, the CO2 conversion was only about 50% so that the separation costs associated with the removal of unreacted CO2 in the synthesis gas tend to counteract the benefits of the higher methane conversion.