The hydrocarbon composition of the bitumen isolated from the Maikop Stratum rock from Northern Azerbaijan was thoroughly studied by the techniques of gas-liquid chromatography and gas chromatography-mass spectrometry. Along with the study of biomarkers from the free aliphatic fraction, the composition of biomarkers occurring as sulfur compounds in the aromatic and polar fractions of the bitumen was investigated. The sulfurized hydrocarbon structures of the aromatic and polar fractions were studied by means of Raney nickel reductive desulfurization reactions. In addition, organosulfur biomarkers of the 5-methyl-2-alkylthiophene series were detected. in which the radicals in the 2-position were derived from either normal or isoprenoid alkanes.