Abstract: The additive described essentially comprises a selected alkoxylated fatty amine or fatty amine derivative and a special metal salt compound, preferably a metal soap. This additive for heavy oils effects a good emulsification or dispersion of asphaltenes and other higher-molecular weight compounds and, in addition, inter alia, increased storage stability, improved pumpability due to decreased viscosity of the oil and longer service lives of the filter systems. In addition, it also effects enhanced combustion of the heavy oils. The effective amount of additive in these oils is 2 to 2000 ppm. The oils described are suitable, in particular, as furnace fuel for industrial plants and power stations and as engine fuel for marine engines.