The composition and distribution of saturated hydrocarbons (alkanes, steranes, and terpanes) of oils from the Ulyanovsk oblast of the Volga-Urals oil-and-gas basin were studied. Wax fractions were isolated from crude oils, and C(48)-C(52) high-molecular-mass n-alkanes, C(35)-C(52) alkylcyclopentanes, and C(24)-C(42) 2- and 3-monomethylalkanes were identified in these fractions. Based on the data on the composition of C(10)-C(36) n-alkanes, C(19)-C(35) terpanes, C(21)-C(30) steranes, and C(40+) alkanes, it was shown that the oils in question were generated by marine organic matter in carbonate sediments. Oil from the Novolabitovskoe field (1981-1992 m) substantially differs for the other oils in terpane and sterane compositions. These differences are supposedly due to another source of organic matter.