Abstract: A method for pretreating a coal hydrogenation feedstock with preheated hydrogen containing a hydrogenation gas under high pressure and at elevated temperature, in a liquid phase slurry system, is disclosed. In this process a mixture of a slurry of finely ground coal and a slurry oil are fed to a preheater before being subjected to a hydrogenation and liquefaction reaction in a cascade of reactors at a pressure of from 100 to 40 bars and a temperature of 420.degree. to 490.degree. C. The reaction products are fed to a hot separator.In the process of the invention, prior to its preheating, a first partial stream of the hydrogenation gas, referred to as the slurry gas, is added to the mixture at process pressure. A second partial stream of the hydrogenation gas is heated by indirect heat exchange with a gaseous hot separator product in a gas heat exchanger.