Concentrations of perylene hydrocarbons were determined in 270 oils and 150 organic matter samples recovered from Cainozoic, Cretaceous. Jurassic and Palaeozoic deposits of the principal oil-bearing provinces of Russia: West Siberia, Uralo-Povolzhye region and Sakhalin island. The highest concentration is observed in oils recovered from Cainozoic deposits. The perylene hydrocarbons content in organic matter of rocks is always significantly higher than in oils of the same deposits. Perylenes, being absent in Palaeozoic oils, were found in some organic matter samples of rocks of Uralo-Povolzhye region and West Siberia. The decrease in perylene content and increase in methyl perylene fraction in oils with age and depth of enclosing deposits were established. The concentration ratio of perylene and its methylated homologues is a reliable indicator of maturation of oils and organic matter
