The effect of a compatibilizer on the properties of corn starch-reinforced metallocene polyethylene-octene elastomer (POE) blends was studied. The compatibility between POE and starch was improved markedly with a acrylic acid-grafted POE (POE-g-AA) copolymer as a compatibilizer. Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, differential scanning calorimetry, and scanning electron microscopy were used to examine the blends produced. The size of the starch phase increased with an increasing content of starch for noncompatibilized and compatibilized blends. The POE/starch blends compatibilized with the POE-g-AA copolymer lowered the size of the starch phase and had a fine dispersion and homogeneity of starch in he POE matrix. This better dispersion was due to the formation of branched and crosslinked macromolecules because the POE-g-AA copolymer had anhydride groups to react with the hydroxyls. This was reflected in the mechanical properties of the blends, especially the tensile strength at break. In a comparison with pure POE, the decrease in the tensile strength was slight for compatibilized blends containing up to 40 wt% starch. The POE-g-AA copolymer was an effective compatibilizer because only a small amount was required to improve the mechanical properties of POE/starch blends.