The structure, biodegradability, and morphological properties of composite materials composed of poly(butylene succinate adipate) (PBSA) and bamboo fiber (BF) were evaluated. Composites containing acrylic acid-grafted PBSA (PBSA-g-AA/BF) exhibited noticeably enhanced compatibility between the two components. The dispersion of BF in the PBSA-g-AA matrix was highly homogeneous as a result of ester formation and the consequent creation of branched and crosslinked macromolecules between the carboxyl groups of PBSA-g-AA and hydroxyl groups in BF. In addition, the PBSA-g-AA/BF composite was more easily processed due to a lower melt viscosity. Each composite was subjected to biodegradation tests in an Acinetobacter baumannii compost. Morphological observations indicated severe disruption of film structure after 1020 days of incubation, and both the PBSA and the PBSA-gAA/BF composite films were eventually completely degraded. The PBSA-g-AA/BF films were more biodegradable than those made of PBSA and exhibited a lower molecular weight and intrinsic viscosity, implying a strong connection between these characteristics and biodegradability. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 1211-1219, 2011