The steady-state kinetics of methanol oxidation over Cu(110) have been studied in the 10(-7) to 10(-3) mbar range. H-2, H2O, and CO2 are found in addition to the main product formaldehyde. The reactive sticking coefficient of methanol reaches 0.2. A pronounced hysteresis is observed when the temperature is cycled. Our data indicate the presence of two rate maxima, one at approximate to 400-520 K and the other at approximate to 900 K. The amplitude of the low-temperature reactivity peak decreases with increasing total pressure, vanishing beyond 10(-3) mbar. High oxygen partial pressures led to a poisoning of the reaction, which was apparently caused by the inhibitory effect of high oxygen coverage on methanol adsorption. (C) 2004 Published by Elsevier Inc.