Abstract: The invention relates to an improved process for making 1,1-diacetoxyethane by reacting methyl acetate and/or dimethylether with carbon monoxide and hydrogen under practically anhydrous conditions, at temperatures of 350.degree. to 575.degree. K., under pressures of 1 to 300 bars, and in the presence of a catalyst system containing noble metals belonging to group VIII of the periodic system of the elements, or compounds thereof, and iodine and/or its compounds. The improved process is effected in the presence of a catalyst system containing, as additional ingredients, an aliphatic carboxylic acid having 1 to 8 carbon atoms, a heterocyclic aromatic compound, in which at least one hetero atom is a quaternary nitrogen atom, and a manganese or rhenium compound.