Solid and microcellular specimens made of poly (3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV)/poly(butylene adipate-co-terephthalate) (PBAT) blends with three different weight ratios (i.e., PHBV/PBAT = 98.5/1.5 (Y1000P), 45/55 (5010P), and 30/70 (6010P), respectively) were prepared via conventional and microcellular injection molding process, respectively. Various properties such as miscibility, cell morphology, thermal, and mechanical properties were investigated. Compared with the microcellular specimens, the solid specimens showed better miscibility. Increasing the PBAT content led to higher specific toughness and strain-at-break, but lower specific modulus and specific strength for both solid and microcellular specimens. In addition, increasing the PBAT content increased the average cell size, but decreased the cell density of the microcellular samples. Finally, the crystallinity of PHBV in the PHBV/PBAT blends decreased significantly with increasing PBAT content for both solid and microcellular specimens. POLYM. ENG. SCI., 50:1440-1448, 2010. (C)2010 Society of Plastics Engineers