Mild thermolysis of resins and asphaltenes from oils of various origins was performed. It was shown that the thermolysis of resins and asphaltenes results in the same saturated products, biomarkers (steranes, terpanes, n-alkanes, and isoprenanes), as in the case of crude oils. Comparison of the distribution of biomarker hydrocarbons in the thermolysis products of resins, asphaltenes, and native oils showed that the organic-matter maturity determined from the value of the sterane index increases in the order resins-asphaltenes-oil. The thermolyzates of resins and asphaltenes contain oleanane, which is not generated in native oils. The ratio between regular C-27-C-29 steranes in the asphaltene thermolysis products is closer to that in crude oils. The pristane/phytane ratio in the thermolyzates of resins and asphaltenes is very close to that in the parent oils. A potential use of the distribution of saturated biomarker hydrocarbons generated in thermolyzates for genetic assignment of crude oils is shown.