Modified nano-fumed silica (mn-silica)/poly(glycerol-sebacate-citrate), in which mn-silica loadings varied from 0 to 20 phr, were prepared by in situ polymerization and surface modification. The influence of mn-silica loadings on the structure and properties of the composites was studied. Scanning electron microscope (SEM) and transmission electron microscope (TEM) photos showed that the mn-silica dispersed well as nano-scale network in the matrix, and exhibited good interfacial bonding with the matrix. The mn-silica filled composites exhibited excellent comprehensive properties relative to the unfilled elastomers. Specially, the tensile strength improved from 0.9 MPa to 5.3 MPa. Results of the in vitro degradation test suggested that mn-silica loading could adjust the degradation rate of the composites in simulated body fluid solution. The MTT colorimetry with L929 cells substantiated that the introduction of mn-silica weakened the cytotoxicity of elastomers and made the composites accepted as qualified biomedical materials. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 1612-1620, 2012