The mechanical and morphological properties of polypropylene/nylon 6 blends compatibilized with PP grafted with maleic anhydride (PP-g-MA) and styrene/ethene-co-butene/styrene grafted with maleic anhydride (SEBS-g-MA) are studied using a special version of a factorial design known as extreme vertices. Properties examined include yield stress, modulus, elongation, toughness, impact strength and morphology. Comparisons are made between various treatment combinations (i.e. a variety of blends] and polypropylene homopolymer using various statistical methods including analysis of variance (ANOVA), Scheffe's Test and Duncan's Multiple Range Test. Significant differences were found for yield stress, modulus, elongation, toughness and impact strength for specific treatment combinations versus PP as well as on average. Ternary diagrams are used to plot response surfaces of the measured data illustrating the main effects and interactions involved, while allowing correlations to be made with blend morphology. Indications from test results and analysis of response surfaces show a strong relationship between nylon/compatibilizer ratio and mechanical properties.