Hydrotreatment for petroleum cuts with offretite

A hydrotreatment process for petroleum cuts containing sulfur for simultaneous desulfurization and improvement of flow properties by conversion of n-paraffins, comprising contacting the sulfur containing cuts at a temperature of 200.degree. to 500.degree. C., a pressure of 1 to 80 bars, a liquid spatial velocity of the load (LSV) of 0.3 to 6 m.sup.3 /m.sup.3 /h, with hydrogen at a hydrogen/hydrocarbon molar ratio between 2 and 10, in the presence of a catalytic system based on a synthetic zeolitic crystalline silico aluminate of the offretite structure having the chemical formula (M.sub.1,M.sub.2 . . . ).sub.2 (Al.sub.2 O.sub.3)(Sio.sub.2).sub.y wherein y is between 10 and 50, M.sub.1 and M.sub.2 are selected from cations of the groups I and II of the Periodic Table of Elements, the offretite is impregnated with a mixture of oxides or sulfides of at least one metal selected from the group consisting of chromium, molybdenum and tungsten with an oxide or a sulfide of at least one metal selected from the group consisting of iron, cobalt and nickel.