The composition of the organic matter (OM) of bitumen-bearing sand and oil shale from the Bayan Erkhet deposit (Mongolia) has been studied. It has been shown that bitumenoids of both samples are high-resin, low-sulfur materials; higher C-25-C-33 homologues predominate among alkanes and C-29 steranes are the most abundant among steranes. The presence of biohopanes in the sandstone and shale bitumenoids indicates a low maturity of the source OM, and the presence of 25-norhopanes shows that their OM is biodegraded. Monoaromatic hydrocarbons are represented by naphthenosubstututed compounds. As alkylnaphthalenes and alkylphenanthrenes, the methylsubstituted isomers have been identified. DOI: 10.1134/S0965544112060102