Abstract: A hydrofining process wherein an olefinic naphtha hydrocarbon feed in vapor phase is contacted, in a fixed bed, with a catalyst of small particle size at low pressure. Suitably, a catalyst of average particle size no greater than, or less than about 1/20 inch is employed. Preferably, the catalyst is of average particle size ranging from about 200 microns to about 1/20 inch, and more preferably the catalyst is of average particle size ranging from about 1/40 inch to about 1/20 inch. By the use of such catalyst at total pressures ranging from about 60 to about 300 psig, preferably from about 80 to about 200 psig, it has been found that the rate of hydrodesulfurization of the naphtha feed is considerably increased, and yet there is significantly less saturation of the olefins, and other nonreactive hydrocarbons with hydrogen.