Post-consumer PET/ low-density polyethylene (LDPE) blends were prepared in a twin-screw extruder. Ethylene-octene rubbers grafted with different amounts of maleic anhydride (POF) were used as compatibilizer precursors to improve the compatibility between the two immiscible polymers. The improvement of compatibility was checked by electron scanning microscopy (SEM) by evaluating the dimensions and shape of dispersed LDPE domains. Moreover the tensile properties of blends were studied by recording stress-strain curves and the impact properties were determined by Izod Impact tests. Useful correlations between the degree of modification of POF, morphological features and mechanical performances were thus obtained. In particular a critical value of the functionalization degree of POF was found to be necessary to assure high impact strength, stiffness and ductility to the blends.