The reaction of methanol to form hydrogen and carbon dioxide on metal surfaces has regained a lot of interest with the advent of methanol powered fuel cells. This fact together with the rather recent detailed structural description of the Cu – O stripe phase is the reason for a detailed investigation of the interaction of methanol with this surface. The adsorption and subsequent reaction of methanol on Cu(110) and on the Cu – O stripe phase is investigated using reflection absorption infra red spectroscopy (RAIRS) and density functional theory (DFT) calculations. From thermal desorption measurements it is known that methanol has a low sticking coefficient on the clean Cu(110) surface. Nevertheless, the reaction of methanol to formaldehyde and to carbon monoxide and hydrogen does take place after an exposure of 50 Langmuir. On the Cu – O stripe phase methanol shows a high sticking coefficient and the reaction products are formaldehyde, water, carbon dioxide and carbon monoxide and hydrogen. The RAIRS measurements as a function of exposure and as a function of surface temperature show the intermediates that are stable under different conditions explaining the reaction mechanisms. DFT calculations enable a clear determination of the different vibrational frequencies of methanol and all reaction intermediates on the two copper surfaces.