A process for preparing an aliphatic hybrid ester/ether polyol, comprising simultaneously (A) transesterifying, and (B) alkoxylating a mixture comprising: (a) at least one ester group containing compound which is free of ether groups, and is selected from the group consisting of triacylglycerols, fatty acid esters, fatty acid polyesters, alkyl esters, alkylene di-esters, alkylene tri-esters, alkylene polyesters and mixtures thereof, wherein (a) said ester group containing compound comprises methyl caprylate, methyl laurate, methyl stearate, dimethyl malonate, dimethyl adipate, soybean oil, palm oil, or mixtures thereof; and, (b) at least one or more hydroxyl group containing compound which is free of ester groups, and is selected from the group consisting of alcohols, polyols, polyether polyols, hyperbranched polyols and mixtures thereof; with the proviso that said mixture has an overall hydroxyl number of less than or equal to 350; with at least one alkylene oxide; in the presence of a mixture of catalysts comprising (a) at least one DMC catalyst, and (b) at least one non-alkaline transesterification catalyst. (A) transesterifying, and (B) alkoxylating a mixture comprising: (a) at least one ester group containing compound which is free of ether groups, and is selected from the group consisting of triacylglycerols, fatty acid esters, fatty acid polyesters, alkyl esters, alkylene di-esters, alkylene tri-esters, alkylene polyesters and mixtures thereof, wherein (a) said ester group containing compound comprises methyl caprylate, methyl laurate, methyl stearate, dimethyl malonate, dimethyl adipate, soybean oil, palm oil, or mixtures thereof; and, (b) at least one or more hydroxyl group containing compound which is free of ester groups, and is selected from the group consisting of alcohols, polyols, polyether polyols, hyperbranched polyols and mixtures thereof; with the proviso that said mixture has an overall hydroxyl number of less than or equal to 350; with at least one alkylene oxide; in the presence of a mixture of catalysts comprising (a) at least one DMC catalyst, and (b) at least one non-alkaline transesterification catalyst. a mixture comprising: (a) at least one ester group containing compound which is free of ether groups, and is selected from the group consisting of triacylglycerols, fatty acid esters, fatty acid polyesters, alkyl esters, alkylene di-esters, alkylene tri-esters, alkylene polyesters and mixtures thereof, wherein (a) said ester group containing compound comprises methyl caprylate, methyl laurate, methyl stearate, dimethyl malonate, dimethyl adipate, soybean oil, palm oil, or mixtures thereof; and, (b) at least one or more hydroxyl group containing compound which is free of ester groups, and is selected from the group consisting of alcohols, polyols, polyether polyols, hyperbranched polyols and mixtures thereof; with the proviso that said mixture has an overall hydroxyl number of less than or equal to 350; with (a) at least one ester group containing compound which is free of ether groups, and is selected from the group consisting of triacylglycerols, fatty acid esters, fatty acid polyesters, alkyl esters, alkylene di-esters, alkylene tri-esters, alkylene polyesters and mixtures thereof, wherein (a) said ester group containing compound comprises methyl caprylate, methyl laurate, methyl stearate, dimethyl malonate, dimethyl adipate, soybean oil, palm oil, or mixtures thereof; and, (b) at least one or more hydroxyl group containing compound which is free of ester groups, and is selected from the group consisting of alcohols, polyols, polyether polyols, hyperbranched polyols and mixtures thereof; at least one alkylene oxide; in the presence of a mixture of catalysts comprising (a) at least one DMC catalyst, and (b) at least one non-alkaline transesterification catalyst. (a) at least one DMC catalyst, and (b) at least one non-alkaline transesterification catalyst. <EOS>