The crystallization of long-chain n-paraffins C28, C32, and C36 and of their binary mixtures from the melt and from solution in decane was investigated by differential scanning calorimetry (DSC). Both rotator and monoclinic phases were observed in crystallization from the melt, but a single monoclinic phase is observed from decane solution. The binary solution of C36 + C32 in decane forms a solid solution which shows only one thermal peak during cooling and heating, whereas C36 + C28 crystallizes separately, showing two peaks from decane solution. A solid rotator phase forms first from a mixture of C36 + C28 cooled from the melt, followed at lower temperatures by a eutectic showing separation of the paraffins in a solid-state conversion to the monoclinic forms. The addition of microcrystalline poly(ethylene-butene) (PEB) random copolymers to long-chain paraffin solutions in decane induces heterogeneous nucleation on cooling.