Blends of nylon 6 and polyethylene were investigated over a range of compositions. The polyethylenes used were grafted with maleic anhydride and, thus, have the potential to react with the amine end groups of nylon 6 during melt processing. This study focuses on the effects of the concentration, viscosity and functionality of the maleated polyethylenes (PE-g-MA) on the rheological, morphological, and mechanical properties of nylon 6/PE-g-MA blends. The impact properties of these blends are strongly influenced by the amount and type of maleated polyethylene used. A low viscosity maleated polyethylene was shown to be ineffective in toughening nylon 6; this was because of the propensity of polyethylene to become continuous even when nylon 6 was the majority component. Two higher viscosity maleated polyethylenes were able to produce blends with high impact strength and excellent low temperature toughness over a range of compositions. It was demonstrated that polyethylene materials containing a very law degree of anhydride functionality can generate blends with excellent impact properties. A brief portion of this study focused on ternary blends of nylon 6, maleated polyethylene and nonmaleated polyethylene; in general, the impact properties of these blends improved as the nylon 6 molecular weight increased and as the ratio of maleated polyethylene to nonmaleated polyethylene increased.