The decomposition of methanol to carbon monoxide and hydrogen can be catalyzed at 250 degrees C over nickel supported on silica. The activity of the catalyst prepared by a sol-gel method increases with an increase in the content of nickel up to 40 wt.% while that for the sample prepared by an impregnation technique almost reaches a plateau at the nickel content of 10 wt.%. The activity does not relate simply to the nickel surface area of the sample, but it depends on the amounts of carbon monoxide and hydrogen strongly adsorbed on the catalyst. Small nickel particles are disadvantageous in the reaction.