The flowability and thermal behavior of waxy solutions with and without an ethylene-vinyl acetate copolymer (EVA) have been studied. The drastic changings of pour point depression (Delta T-pp) and the crystallization in four waxy solutions were observed. These changes were linear with the U-interaction parameters between EVA and wax in different solvents, suggesting that the efficiency of EVA pour point depressant depends on its compatibility with wax, which is affected by solvent.