Slurry-phase methanol synthesis via methyl formate was carried out at 373 K and an initial pressure of 5 MPa using alkoxide and a physical mixture of CuO and Cr2O3 as a catalyst. Methanol productivity was enhanced with prolonged milling of the mixture. Characterization of the mixtures by physical adsorption, X-ray diffraction and transmission electron spectroscopy suggested that long-term milling brought about a lattice disorder in the crystals of CuO and/or Cr2O3 as well as an enlarged surface area, which contribute to an increase in catalytic activity.