The structural group characteristics of resins and asphaltenes, isolated from high-sulfur natural asphaltite of the Ivanovskoe oilfield in Orenburg oblast and the liquid products of its conversion in a flow of supercritical water (SCW) at 400 degrees C and 30 MPa with and without admixture of zinc or aluminum, have been investigated. It has been shown that as a result of SCW treatment, the molecular weight of the resins and asphaltenes decreases two- to fivefold in comparison with the components of the initial asphaltite. This is determined by a decrease in the number of structural blocks in the molecules which become more compact due to the decrease both in the number of rings, predominantly naphthenic ones, in the blocks and in the number of carbon atoms in the aliphatic substituents. The fraction of aromatic carbon atoms substantially increases, and the degree of substitution of the aromatic nucleus decreases in the resins and asphaltenes isolated from the conversion products. The differences in the structural chemical characteristics of the resins and asphaltenes manifest themselves to a greater extent in the case the metal admixtures.