The molecular composition of NSO heterocyclic aromatic compounds in the lube stock fractions of chloroform-extractable bitumenoids isolated from Cambrian shale formation rocks of Kuonam oil shale, which differ in their organic carbon content, was studied. Of the sulfur compounds, C(3)-C(4) alkylbenzothiophenes; dibenzothiophene, its C(1)-C(5) alkyl and naphtheno derivatives; naphthobenzothiophene; and methylnaphthobenzothiophenes were identified. Among the oxygen compounds, unsubstituted dibenzofuran, unsubstituted naphthobenzofuran, and their C(1)-C(4) and C(1)-C(2) homologues, respectively, were detected. The nitrogen compounds present in the test fractions were supposed to be 7H-benzo[c]- and 7H-benzo[b]acridin-12-ones and methylbenzoacridin-12-ones.