Using a two-stage hydrogenation process, white oil was produced from fuel oil obtained from a predominantly light naphthenic crude oil. The raw fuel oil used consisted of 6.33 wt % saturates; At the end of hydrogenation, the saturates content of the product was 91.31 wt % as compared with 91.97 wt % obtained for a commercial white oil tested. Over 98 wt % of the sulfur content of the fuel oil was removed. The time of introducing the reactant hydrogen into the reactor affected the rate of saturates formation most.