Blends of poly(beta-hydroxybutyrate) (PHB) and low density polyethylene (LDPE) were prepared in proportions of 100/0, 75/25, 50/50, 27/75 and 0/100 (PHB/LDPE wt.%), with and without oxidized polyethylene wax (OPW, 5 wt.%), and the mechanical, thermal (differential scanning calorimetry and melting flow index, morphological (scanning electron microscopy) and biodegradation (aging in simulated soil) properties were evaluated. The addition of OPW increased the tensile strength and Young's modulus but decreased the elongation at break of the blends. Similarly, OPW increased the T (g) of the pure LDPE and enhanced the melt flow index. Scanning electron microscopy showed that OPW reduced the phase separation of LDPE and increased the biodegradation during aging in simulated soil.