The disproportionation of triethoxysilane was carried out in a fixed-bed flow reactor over the solids obtained by heat-treating calcium hydroxide at various temperatures. In the disproportionation, the reaction proceeding to completeness to afford silane and tetraethoxysilane occurs to far lesser extent : predominantly diethoxysilane is obtained together with tetraethoxysilane. Dimethoxysilane is obtained by the disproportionation of trimethoxysilane also over the heat-treated calcium hydroxide.