This invention relates to the catalytic hydrogenation of edible oils of animal and vegetable origin. Catalytic hydrogenation according to the invention improves the keeping qualities of such edible oils without impairing their nutritional value or edibility. This is achieved by selectively hydrogenating the triply unsaturated forms of the fatty acids contained in the oil to doubly unsaturated forms using a supported catalyst. The catalyst used contains one or more of the metals Fe, Co, Ni and the platinum group metals and the support may be of extended surface or particulate form, for example, C, stainless steel, ceramics and Fe--Cr--Al--Y alloys.