Blends of polyamide 6 (PA6) and elastomeric ethylene-octene copolymer (EOR), with and without maleated EOR (EOR-MA) were studied. EOR-MA with various amounts of grafted MA and gel content were prepared by reactive extrusion. The effects of EOR-MA characteristics and composition on the morphology, thermal and mechanical properties of the blends were investigated. EOR-MA was found to promote the toughness efficiency of PA6 remarkably. High impact resistance was achieved by the use of EOR-MA containing less than 2% gel. The content of MA grafted on EOR-MA in the range of 0.5%-1.0% gave a similar effect on the blend properties. The blend containing 20% of EOR grafted with 1% MA exhibited twenty times higher impact strength (1000 J/m) than pure PA6 (55 J/m). The presence of EOR-MA in the blends led not only to a drastic reduction in the dispersed particle size, but also to some changes in fracture mechanisms, thus enhancing the impact resistance of the blends.