In this study, the effects of unmodified and surface modified multiwalled carbon nanotube (MWCNT) and graphene on the mechanical, thermal and non-isothermal crystallization kinetics of poly(butylene succinate) (PBS) were investigated. The surface of carbon nanofillers were modified by oxidation and/or esterification reactions. PBS nanocomposites containing 0.25, 0.5 and 1 wt% modified and unmodified carbon nanofillers were prepared by melt blending method in a microcompounder (Xplore Instruments MC15, The Netherlands). The dispersion of carbon nanofillers in PBS matrix was evaluated by scanning electron microscope (SEM) and transmission electron microscope (TEM). Common kinetic models such as Avrami and combined Avrami-Ozawa were used to evaluate non-isothermal crystallization behaviour of PBS nanocomposites by using differantial scanning calorimeter (DSC). Besides, a polarized optical microscope (POM) equipped with a hot-stage was used to examine the morphology during the crystal growth. Moreover, mechanical and thermo-mechanical properties of the nanocomposites were evalutaed by tensile and dynamic mechanical analysis (DMA), respectively.