The gas-phase reactions of O+ with methanol are investigated by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. Absolute rate constants and branching ratios of the competing reactions are derived. The reaction proceeds mainly via "hydride transfer" yielding CH3O+ product ions. Isotopic studies suggest that both hydroxyl, (OH) and methyl (CH3) hydrogen atoms are abstracted. Several lighter fragment ion products are also detected. The CH3O+ primary products react efficiently further to yield the protonated methanol ion, CH3OH2+.