Process for the production of low-sulfur diesel gas oil

A process for the production of a low-sulfur diesel gas oil from a petroleum distillate having a sulfur content of 0.1 to 2.0% by weight and a boiling point of 150.degree. to 400.degree. C., the process comprising contacting the petroleum distillate with hydrogen in the presence of a hydro-treating catalyst which has at least one metal or its oxide or sulfide and a porous carrier, wherein said metal or its oxide or sulfide has a hydro-treating activity and is supported on said porous carrier, at a temperature of 350.degree. to 450.degree. C., and a pressure of 45 to 100 kg/cm.sup.2 in the first step to thereby produce materials having a sulfur content of 0.05% by weight or lower, and contacting further the materials issued from the first step with hydrogen in the presence of a hydro-treating catalyst which has at least one metal or its oxide or sulfide and a porous carrier, wherein said metal or its oxide or sulfide has a hydro-treating activity and is supported on said porous carrier, at a temperature of 200.degree. to 300.degree. C., and a pressure of 45 to 100 kg/cm.sup.2 in the second step to thereby produce the low-sulfur diesel gas oil having a Saybolt color number of -10 or higher and a sulfur content of 0.05% by weight or less, wherein the metal of the hydro-treating catalyst in each step is selected from the group consisting of chromium, molybdenum, tungsten, cobalt, nickel and iron, and wherein lighter fractions are not removed from the materials produced in the first step before said materials are subjected to the second step.