Pt/Al2O3 and Pd/Al2O3 catalysts have been prepared from chlorine-free precursors and investigated for the combustion of methane under lean, stoichiometric, and rich conditions using dilute mixtures. It has been found that under lean conditions, and at low conversions under stoichiometric or rich conditions, Pd/Al2O3 is a more effective catalyst. However, at higher conversions with stoichiometric or rich mixtures Pt/Al2O3 is a more active catalyst. This change over between Pd/Al2O3 and Pt/Al2O3 is associated with a ’light-off’ effect observed with Pt/Al2O3 catalysts. Various possible explanations for these effects are discussed. With the Pt/Al2O3 catalysts there is no evidence of a particle size effect, which is in contrast to reports in the literature that the methane combustion reaction is structure sensitive. Reasons for these variations, including the possible inhibition of activity by chlorine used in many catalyst preparations, are discussed. It is concluded that platinum can be a more effective catalyst than palladium for methane combustion under real conditions and that, in consequence, platinum may play an important role in multimetallic catalysts for emission control for natural gas vehicles.