AbstractMechanical properties, molecular weight, X‐ray diffraction, and differential scanning calorimetry (DSC) characterization of blends of virgin high‐density polyethylene (HDPE) with two types of recycled material were investigated. The recycled came from urban plastic waste; one kind was only washed and grounded and the other was extruded and pelletized to remove most of contaminant particles. Starting with the 30/70 virgin/grounded recycled and 50/50 virgin/pelletized recycled blends the recycled content was increased in both blends and compatibilizing agents were used to increase the blend performance. A mixture of phenolic antioxidants and phosphite costabilizers under the name of Recycloblend™, ethylene vinyl acetate (EVA) copolymer, low‐density polyethylene (LDPE), and linear low density polyethylene (LLDPE) were used as compatibilizers. The effect of these additives and the recycled content on the performance of extrusion blow‐molded bottles was determined. The results suggest that blends of virgin/grounded recycled and virgin/pelletized recycled HDPE, in general, were not significantly different among each other and both had a quite similar behavior than the virgin HDPE when compatibilizing agents were used. The addition of compatibilizing agents yielded a material with properties similar to those for the virgin HDPE, helping to reduce the effect of polymers degradation on the rheological and mechanical behavior, with Recycloblend and LLDPE being the most effective for the blends with grounded recycled material, and LLDPE y EVA, for the blends with pelletized recycled. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3696–3706, 2006