An ethylene-acrylic acid copolymer (EAA), either alone or combined with a low molar mass bis-oxazoline compound (PBO), has been used as a compatibilization promoter for blends of polyamide-6 (PA6) with low-density polyethylene (LDPE). The effect of compatibilization on blend processability in injection molding operations and on the properties of the molded specimens has been studied. In the absence of compatibilization, the injection molded articles were shown to have low-quality surface appearance and poor mechanical properties. Both these characteristics were appreciably improved as a result of reactive compatibilization of the blends with EAA and, even more, with the EAA-PBO couple. in fact, the finished articles prepared by injection molding of the quatemary blends were shown to possess good surface appearance, fine and stable morphology and satisfactory mechanical properties. The results confirm the conclusion of a previous study, i.e., that the PBO fourth component may promote the in situ formation of PA6-g-EAA copolymers, by reaction with both the functional groups of PA6 and the carboxyl groups of EAA. (C) 2004 Society of Plastics Engineers.