Blends of nylon-6/ethylene-propylene rubber(EPR)/ethylene-acrylic ester-maleic anhydride copolymer(EAM) In which the EPR and the EAM were used as impact modifiers were prepared by melt blending and the structure-property relationships of the blends were studied. It was observed that the size and the number of discrete particles were decreased as the EAM content was increased at the fixed levels of the 20 wt% modifiers. Graftomers seemed to be formed from the reaction between the nylon-6 and the EAM and the dispersion of the modifiers was improved. The impact strength of the blends showed maximum as the EAM content was increased. It is postulated that the synersistic toughening of the nylon-6 by the modifiers is attributable to the relatively large particles of the EPR effective for craze formation an well as the fine dispersion of the EAM favoring shear yielding. Tensile properties and crystallization behaviors of the blends depending on the EAM content are discussed based on the morphology of the blends.