The thermal transformations of components of the residue (boiling point above 350 degrees C) of Zuunbayan heavy, high-wax oil (Mongolia) in the presence of cogeneration plant flyash ferrospheres and sunflower oil have been studied. The use of the additives made it possible to obtain additional amounts of distillate fractions (IBP-360 degrees C). The physicochemical characteristics and composition of the products have been determined. The structural-group characteristics of the resin-asphaltene components of the feed petroleum residue and the products of its thermal conversion in the presence of sunflower oil and flyash ferrospheres have been compared. The presence of sunflower oil and ferrospheres leads to a decrease in the molecular weight of the resins and asphaltenes isolated from thermolysis products. The number of naphthenic and paraffinic carbon atoms in resin and asphaltene molecules decreases, and the proportion of aromatic atoms markedly increases.