We report a study of the solid state microstructure and crystallization kinetics of poly(butylene succinate) (PBSu) reinforced with nanofillers of different shapes, sizes and geometries such as silver, silica (SiO2), multi-walled carbon nanotubes (MWCNTs) and graphene oxide (GO). The solid state structure of neat polymer and nanocomposites were investigated by X-ray diffraction (XRD), polarized optical microscopy (POM) and transmission electron microscopy (TEM). The results indicated that the nanocomposite samples exhibited enhanced crystallinity and nucleation density, along with smaller spherulite size. Additionally, the spherical nanofillers were dispersed more uniformly in the polymeric matrix, than the other two filler types. The crystallization kinetics under both isothermal and dynamic conditions were also studied and as was expected, the nanocomposite samples, crystallize at higher rates due to the increased number of nucleation sites, as was calculated with Avrami, Dobreva and Friedman's methods. From the crystallization study it was found that the nanocomposite filled with Ag nanoparticles exhibited the highest rates from all other fillers followed from SiO2 and MWCNTs while GO showed the lowest rates. (C) 2014 Elsevier B.V. All rights reserved.