Abstract: Process for the conversion of heavy feedstocks selected from heavy crude oils, distillation residues from crude oil or catalytic treatment, “visbreaker tars”, “thermal tars”, bitumens from “oil sands” liquids from coals of different origins and other high boiling feedstocks of a hydrocarbon origin, comprising the following steps: •mixing the heavy feedstock with a suitable hydrogenation catalyst and sending the mixture obtained to a first hydrotreatment area (HT1) to which hydrogen or a mixture of hydrogen and H2S are introduced; •sending the effluent stream from the first hydrotreatment area (HT1), containing the hydrotreatment reaction product and the catalyst in dispersed phase, to a first distillation area (D1) having one or more flash steps and/or atmospheric distillation and/or vacuum distillation whereby the various fractions coming from the hydrotreatment reaction are separated; •sending at least part of the distillation residue (tar) or liquid leaving the flash unit of the first distillation area (D1