In this study, the nanocomposites of poly(butylene succinate) (PBS) and TiO2 nanofibers were first synthesized via in situ polymerization. Molecular weight, morphology, and thermal properties of the nanocomposites were characterized. As the weight percentage of TiO2 nanofibers increased from 0 to 2%, the molecular weight of PBS in the nanocomposites decreased gradually compared with that of pure PBS. In morphology, the nanocomposites were constituted by free PBS and PBS-grafted TiO2 nanofibers (PBS-g-TiO2), which were proved by the Fourier transform infrared, scanning electron microscopy (SEM), and transmission electron microscopy. In addition, the SEM demonstrated the strong interfacial interaction and homogeneous distribution between TiO2 nanofibers and PBS matrix. The thermal properties determined by differential scanning calorimetry and thermogravimetric analysis included the increasing of cold crystallization temperatures, the melting temperatures, and the thermal stability. Besides, the crystallinity and the rate of crystallization of the nanocomposites were enhanced, which were also observed by the X-ray diffraction. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012