Process for producing low density low-sulfur crude oil as feedstock to refinery processes in which a high density, starting crude oil is divided into a base stream and a dilution stream. The dilution stream is separated into a straight run light fraction, at least a medium fraction and an asphaltic residue. At least the medium fraction is subjected to hydrocracking. The hydrocracked fraction and the light fraction are mixed with the base stream and a crude oil of low density and low sulfur content is recovered.