Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) was used to make composite scaffolds for bone tissue engineering in our previous studies. To control the degradation rate and process of composite scaffolds, PHBV was blended with poly(L-lactic acid) (PLLA), which has a much higher degradation rate than PHBV, and PHBV/PLLA blends were used as polymer matrices for composite scaffolds. Composite scaffolds based on these blends and containing nano-sized hydroxyapatite (nHA) were fabricated using an emulsion freezing / freeze-drying technique. Non-porous films of PHBV/PLLA blends were prepared using the solvent casting method. In vitro degradation tests of non-porous PHBV/PLLA blends and porous composite scaffolds were conducted by immersing samples in phosphate buffered saline (PBS) for various periods of time. It was found that the composition of polymer blends affected water uptake of films and scaffolds. For PHBV/PLLA-based scaffolds, the incorporated nHA particles also significantly increased water uptake within the initial immersion time. Both PHBV/PLLA blends and composite scaffolds underwent rapid weight losses within the first few weeks. The degradation of composite scaffolds arose from the dissolution of nHA particles and degradation of the PLLA component of polymer blends. Composite scaffolds exhibited enhanced adsorption of bovine serum albumin (BSA), a model protein, in the current study.