Kenaf fiber reinforced composites were prepared via melt mixing using completely biodegradable poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(butylenes adipate-co-terephthalate) (PBAT). Kenaf fibers were used as received and after chemical treatments aimed to improve fibermatrix adhesion. The thermal, mechanical, and morphological properties of obtained composites were compared. Thermal measurements have shown no improvement in the thermal stability of PHBV due to reinforcing fibers, whereas detrimental effects have been evidenced for PBAT. Flexural and impact tests have emphasized benefits of chemical modifications depending on the polymer matrix nature as a consequence of an increased interaction at the fibermatrix interface, also highlighted by scanning electron microscopy observations. (c) 2012 Wiley Periodicals, Inc. Adv Polym Techn 32: E313E322, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21282