For converting ethanol to a diesel fuel base stock: a reaction stage (a) of contacting the ethanol with an acid catalyst, amorphous or structured, predominantly mesoporous, at a temperature of 300° C. to 500° C., at a pressure of 2 to 10 MPa and at a WHSV of 0.2 to 4 h−1, producing a gas phase, an organic liquid phase and an aqueous liquid phase, and —a stage (b) of separating the gas phase, the organic liquid phase and the aqueous liquid phase at a pressure close to the reaction pressure, and recycling at least part of the gas phase separated in stage (b) to stage (a), and hydrogenating at least part of the organic liquid phase separated in stage (b).