Process for dehydrating aliphatic alcohols admixed with water wherein the alcohols-water mixture is subjected to a first fractionation in the presence of a selective solvent, giving a vapor effluent containing dehydrated light alcohols and a liquid phase containing heavy alcohols, water and the selective solvent, said liquid phase being subjected to a second fractionation giving as vapor effluent an hetero-azeotropic mixture of water and heavy alcohols and, as liquid effluent, the selective solvent, which is fed back, said hetero-azeotropic mixture being condensed and separated into:(a) a light phase of high alcohol content which is subjected to a third fractionation giving a vapor effluent which is fed back and dehydrated heavy alcohols as liquid effluent, and(b) a heavy phase which is subjected to a fourth fractionation giving a vapor effluent which is fed back and water as liquid effluent.