A process for the refining of crude oil comprising the following steps: • feeding the crude oil to one or more atmospheric distillation units in order to separate various streams; • feeding the heavy residue(s) separated in the atmospheric distillation unit(s), to the sub-atmospheric distillation unit, separating at least two liquid streams; • feeding the vacuum residue separated in the sub-atmospheric distillation unit to the conversion unit comprising at least one hydroconversion reactor in slurry phase into which hydrogen or a mixture of hydrogen and H 2 S is fed in the presence of a suitable dispersed hydrogenation catalyst with dimension ranging from 1 nanometer to 30 microns in order to obtain a product in vapour phase, which is subjected to one or more separation steps obtaining fractions in both vapour phase and liquid phase, and a by-product in slurry phase; • feeding the lighter separated fraction obtained in the sub-atmospheric distillation unit to a hydrodesulfurization unit of light gasoils; • feeding the liquid fraction separated in the hydroconversion unit, having a boiling point higher than 350°C, to a hydrodesulfurization and/or hydrocracking unit of heavy gasoils (HDS/HDC); • feeding the liquid fraction separated in the hydroconversion unit, having a boiling point ranging from 170 to 350°C, to a hydrodesulfurization unit of medium gasoils; • feeding the liquid fraction separated in the hydroconversion unit, having a boiling point ranging from the boiling point of the C 5 products to 170°C, to a desulfurization unit of naphtha; • feeding the liquid stream separated in the atmospheric distillation unit, having a boiling point ranging from the boiling point of the C 5 products to 170°C, to said desulfurization unit of naphtha, characterized in that the hydroconversion unit comprises, in addition to one or more hydroconversion reactors in slurry phase, a separator, to which the slurry residue is sent, followed by a second separator, an atmospheric stripper and a separation unit. • feeding the crude oil to one or more atmospheric distillation units in order to separate various streams; • feeding the heavy residue(s) separated in the atmospheric distillation unit(s), to the sub-atmospheric distillation unit, separating at least two liquid streams; • feeding the vacuum residue separated in the sub-atmospheric distillation unit to the conversion unit comprising at least one hydroconversion reactor in slurry phase into which hydrogen or a mixture of hydrogen and H 2 S is fed in the presence of a suitable dispersed hydrogenation catalyst with dimension ranging from 1 nanometer to 30 microns in order to obtain a product in vapour phase, which is subjected to one or more separation steps obtaining fractions in both vapour phase and liquid phase, and a by-product in slurry phase; • feeding the lighter separated fraction obtained in the sub-atmospheric distillation unit to a hydrodesulfurization unit of light gasoils; • feeding the liquid fraction separated in the hydroconversion unit, having a boiling point higher than 350°C, to a hydrodesulfurization and/or hydrocracking unit of heavy gasoils (HDS/HDC); • feeding the liquid fraction separated in the hydroconversion unit, having a boiling point ranging from 170 to 350°C, to a hydrodesulfurization unit of medium gasoils; • feeding the liquid fraction separated in the hydroconversion unit, having a boiling point ranging from the boiling point of the C 5 products to 170°C, to a desulfurization unit of naphtha; • feeding the liquid stream separated in the atmospheric distillation unit, having a boiling point ranging from the boiling point of the C 5 products to 170°C, to said desulfurization unit of naphtha,