Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a biodegradable, biocompatible, bio-based bacterial polyester, making it attractive for use in primary packaging applications. However, for flexible packaging, the applications are limited due to its brittleness and narrow processing temperature range. To mitigate the brittleness of PHBV, Cellulose Acetate (CA), with 2.45 degree of substitution, is compostable and may improve the toughness of PHBV. Furthermore, based on the solubility parameters, PHBV and CA are potentially miscible. In this research, PHBV/CA blends were fabricated to investigate the affect on toughness of CA on PHBV, however CA requires plasticization in order to be melt compounded. CA powder was plasticized with triethyl citrate (TEC), a non-toxic additive. Subsequently PHBV pellets were melt compounded with the plasticized CA powder in a twin-screw extruder followed by injection moulding. Our findings suggest a possibility of degradation of TEC and PHBV due to the high processing temperature, as determined by thermogravimetric analysis (TGA). Scanning Electron Microscopy (SEM) micrograph and density measurements revealed increased porosity of PHBV/CA blends. Blends with high plasticized CA had improved impact of 110% relative to virgin PHBV. Different processing temperatures were also assessed to investigate the different properties of the material, and the heat deflection temperature (HDT) of the blend declined by approximately 10 °C when processed at a higher temperature. Acknowledgment This research is financially supported by the Natural Sciences and Engineering Research Council (NSERC), Canada Discovery Grants (Project # 400320); the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) – University of Guelph, the Bioeconomy Industrial Uses Research Program Theme (Project # 030255); and the Ontario Ministry of Economic Development, Job Creation and Trade ORF-RE09-078 (Project #053970).