In this article, maleated- grafted ethylene-co-vinyl acetate (EVA-g-MA) was used as the interfacial modifier for polypropylene /polyamide-6 (PP/PA6) blends, and effects of its concentration on the mechanical properties and the morphology of blends were investigated. It was found that the addition of EVA-g-MA improved the compatibility between PP and PA6 and resulted in a finer dispersion of dispersed PA6 phase. In comparison with uncompatibilized PP/PA6 blend, a significant reduction in the size of dispersed PA6 domain was observed. Toluene-etched micro-graphs confirmed the formation of interfacial copolymers. Mechanical measurement revealed that the addition of EVAg-MA markedly improved the impact toughness of PP/PA6 blend. Fractograph micrographs revealed that matrix shear yielding began to occur when EVA-g-MA concentration was increased upto 18 wt %. (c) 2006 Wiley Periodicals, Inc.