The catalytic activity of magnesium oxide for catalytic combustion of methane was studied. The effects of temperature, space velocity, concentration of the reactants and the influence of catalytically initiated homogenous gas-phase reactions were examined. At a space velocity of 100 000 h-1, the temperature for 10% conversion was lowered by 270-degrees-C compared to an empty reactor. It was also shown that catalytically initiated homogenous gas-phase reactions are significant for the kinetics.