A method and device for the gasification of solid fuels such as bituminous coals, and cokes such as those from bituminous coals, lignite coals, and biomasses, as well as petroleum cokes, that are ground fine and mixed with water or oil to obtain fuel-in-liquid suspensions, so-called slurries, and their gasification together with an oxidizing medium containing free oxygen, by partial oxidation at pressures between atmospheric pressure and 100 bar, and at temperatures between 1200 and 1900° C. in an entrained flow reactor. The method includes slurry preparation and infeed to the reactor, gasification in an entrained flow reactor with cooled reaction chamber contour, full quenching of the crude gas to saturation temperature that may be 180-260° C. depending on the gasification pressure, and wet or dry dust separation. The crude gas is pretreated so that it can be fed to further technological steps such as crude gas conversion, H2S and CO2 removal, and synthesis.