Graphical dependences of the temperatures of crystallization, start and end of crystallization, and of phase hexagonal-rhombic H -> R conversion in the solid state on wax compositions of petroleum paraffin P-1 with ceresines (C-65, C-80), wax (ZW-1), and soft paraffin (SP) are proposed. It is shown that the melting points of paraffin-ceresine mixtures obey an additivity rule provided that the melting points of the mixed components do not differ by more than 15A degrees C. Paraffin P-1, soft paraffins, and waxes crystallize initially in the H and then also in the R phase, and ceresines only crystallize in the R phase.