The effect of catalyst structure on CO2 reforming of methane has been studied in the temperature range 550-850 degrees C with oxide-supported Rh and Ir catalysts under conditions of reaction rate control. It is found that the rate of reaction expressed per unit metal surface area is constant over a wide dispersion range. There is no detectable effect of the pore structure or nature of the support on the reaction rate. By variation of feed composition through addition of steam or oxygen the H-2/CO ratio in the product could be varied.