The properties of metallocene polyethylene (mPE)/polylactic acid (PLA) bio-based blends containing an ethylene-glycidyl methacrylate-vinyl acetate (EGMA-VA) compatibilizer, with or without the annealing effect of PLA were investigated. The results from SEM (Scanning electron microscope) morphology observation revealed that the dispersed PLA particles sizes within the mPE matrix tended to decrease with the added compatibilizer due to the enhanced interfacial interaction. DSC (Differential scanning calorimetry) and XRD (X-ray diffractometer) results indicated that the addition of the compatibilizer completely hindered the cold crystallization and rearrangement crystallization of PLA, even though the additional annealing effect tended to increase the crystallization of PLA. Tensile test results showed the synergistic effects by compatibilization and annealing treatment improved the tensile strength and Young's modulus, up to 38 % and 62 % increase, respectively. With the incorporation of the compatibilizer, the viscosity increased and reached the highest level among all neat resins and blends, which was attributed to the enhanced interfacial interaction between mPE and PLA. Hopefully, the incorporated bio-based PLA materials could be helpful in reducing the use of petroleum-based materials and are beneficial to the environment in terms of the sustainable development concern. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2399-2409, 2013