Conjugate addition of methanol to 3-buten-2-one to form 4-methoxy-butan-2-one proceeds effectively over the solid base catalysts such as alkaline earth oxides, strontium hydroxide, barium hydroxide. and alumina supported potassium fluoride and hydroxide at a reaction temperature of 273 K. The catalytic activities of magnesium oxide, calcium oxide, and alumina supported KF catalyst were not much affected by exposure of the catalysts to carbon dioxide or air.