The intrinsic steady-state kinetics of the partial oxidation of methanol to formaldehyde over a commercial Fe-Mo catalyst has been studied experimentally in a differentially operated reactor at temperatures of 230¿260 °C, over a wide range of methanol and oxygen concentrations. The principal products found were formaldehyde, water, dimethyl ether (DME) and dimethoxymethane (DMM). The kinetics of the formaldehyde formation from methanol could be well described with Langmuir¿Hinshelwood kinetics, assuming two different metal oxide sites, one containing adsorbed oxygenates and the other one containing lattice oxygen. The presence of water vapor lowered the formaldehyde formation rate significantly, especially at lower water partial pressures. These results could be well explained in terms of competitive adsorption of water with methanol on the free active catalyst sites.