A new method of preparation of alkali-promoted Ru/MgO catalysts, based on a sol-gel procedure, starting from magnesium ethoxide, Ru-3(CO)(12) and a cesium compound has been designed. The gels were subjected to an activation/reduction procedure to substantially obtain Ru-CsOH/MgO. The activated catalysts were tested in ammonia synthesis at atmospheric pressure. It was clear that the sol-gel prepared Cs-promoted Ru/MgO catalysts are much more active, under the same reaction conditions, than the analogous catalysts prepared by impregnation procedures.