Understanding the structure-property relationship in polymer/layered silicate nanocomposites is of fundamental importance in designing materials with desired properties. To understand these relations in the case of poly(butylene succinate) (PBS)/organically modified layered silicate (OMLS) nanocomposites, we studied the rheological properties of these materials in detail, because the rheological behavior of polymer/OMLS nanocomposites is strongly influenced by their nanostructure and the interfacial characteristics. For this reason, a series of PBS/OMLS nanocomposites were prepared using a simple melt intercalation technique. Two different types of OMLS, montmorillonite (mmt) modified with octadecylammonium chloride and saponite (sap) modified with quaternary hexadecyl tri-n-butylphosphonium bromide, were used for the nanocomposite preparations. The structure of nanocomposites in the nanometer scale was characterized using wide-angle X-ray diffraction (WAXD) analyses and transmission electron microscopy (TEM) observations. A flocculated structure has a strong effect on mechanical properties (both in solid and melts) and various other materials properties.