A study was carried out on the chemical group composition of oil ceresins along with their thermal and physicochemical properties. The decisive role of their normal hydrocarbon component in determining the mechanical strength of these materials was elucidated. A graph relating melting point with molar mass was constructed for commercial samples of solid paraffin-containing oil products and for isolated hydrocarbons, some of which form complexes with carbamide. The average molar mass and melting point of the oil paraffins and complex-forming hydrocarbons of ceresins and waxes correspond to the largest-molecular, highest-melting, longest-chain n-alkane of their primary fraction.