Resins of Usa oil and their four fractions obtained by column chromatography have been studied. Changes in the structural parameters of the resins and the product composition for thermolysis of the fractions at temperatures of 200-245 and 450-495A degrees C have been revealed. The thermolysis of resins results in gas, lube oils (hydrocarbons), secondary resins, asphaltenes, and solid products. The resin fractions differ in composition; structure; and, as a consequence, thermal stability. Thermal stability strongly depends on the amount of sulfur and its functional type and on the structure of resin molecules. Fractions with the maximum content of alkyl sulfide sulfur are the least stable during thermolysis.