The effects of platinum and palladium catalysts on the enhancement of methanol combustion were investigated in a high pressure flow reactor and in a single-cylinder, D.I. Diesel engine. Initial studies were carried out in the flow reactor to determine the effect of catalyst temperature and equivalence ratio on the products of methanol combustion. Afterwards, Diesel engine studies were performed with in-cylinder catalysts applied to the exhaust valves in order to maintain high catalyst temperature required for high reactivity. Comparisons were based on performance, combustion characteristics, and emissions.Results of the flow reactor studies show that the catalytic ignition temperature, found to be 570 K, did not vary significantly with equivalence ratio. The Diesel engine experiments revealed that a decrease in glow plug temperature of 400 K was achievable while providing better performance and reduced emissions, including aldehydes, compared to the non-catalytic case.