An integrated analytical study of 30 Devonian (DIII, DI, D3br, Dl, D3lv) and Carboniferous (A4, B2, V1, V3) oil samples from oilfields in the northern, central, and southern parts of Samara oblast has been performed in order to determine the basic characteristics of the composition and the properties of the oils. The results of the comprehensive study of the composition and properties of the crude oils lead to the conclusion that oils from the oilfields in the northern part of Samara oblast significantly differ from those of the southern and central zones. It has been found that the main factor determining the formation of the physicochemical properties of oils in the northern zone is the concentration of higher molecular weight paraffins and asphaltenes, whereas such a factor for the oils of the southern zone is the concentration of higher molecular weight paraffins only. By cluster analysis, the crudes from oilfields in the south of the Samara oblast have been divided into three clusters.