A process of hydrogenating an aliphatic dialdehyde, preferably, a C6-C16 alicyclic dicarboxaldehyde, to form an aliphatic diol, preferably, a C6-C16 alicyclic diol, most preferably, cis/trans-(1,3)(1,4)-cyclohexanedimethanol. The process involves contacting one or more aliphatic dialdehydes in a liquid phase with hydrogen in the presence of a hydrogenation catalyst in a hydrogenation zone and in the presence of water in an amount equal to or greater than 10 weight percent, based on the weight of the total liquid feed to the hydrogenation. The alicyclic dicarboxaldehyde is preferably prepared via hydroformylation of an olefin with subsequent extraction of the alicyclic dicarboxaldehyde product from the hydroformylation product fluid.