Abstract <p>Petroleum products in blubber of a dead Caspian seal washed ashore were studied. It has been shown that the content of petroleum products in the adipose tissue of the Caspian seal (<i>Pusa</i> (<i>Phoca</i>) <i>caspica</i>) is relatively high, but less than the maximum values found previously. Petroleum products in seal blubber include <i>n</i>- and <i>iso</i>-alkanes, alkyl-substituted mono-, bi- and tricycloalkanes, alkylbenzenes, naphthene- and dinaphthenebenzenes, alkylnaphthalenes, and small quantities of acenaphthenes, fluorenes, phenanthrenes, naphthenophenanthrenes, fluoranthenes/pyrenes, and benzthiophenes. Aromatic compounds amount to 50% of all petroleum products, PAHs (including naphthalenes) – to 10%. The majority of aromatic compounds are represented by molecules with 3–12 C atoms in alkyl substituents, while the content of unsubstituted compounds (with the exception of phenanthrene) is relatively small. The distribution of n-alkanes with a high contribution of C₁₇, as well as the prevalence of even n-alkanes C₁₆–C₁₈ and C₂₂–C₂₄, indicates their origin from various biogenic sources. An estimate of the total content of petroleum products in Caspian seal blubber gives about 40% of all extracted compounds.</p>