The pristine sodium montmorillonite (MMT) was organically modified with hexadecyltrimethylammonium bromide (HTAB) at different contents. The organoclay was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy, energy dispersive X-ray techniques, and thermogravimetric analysis. Then, poly(butylene succinate) (PBS) nanocomposites were prepared by melt-mixing process using maleic anhydride-grafted PBS (PBS-g-MA) as compatibilizer. It was found that the mechanical properties of PBS nanocomposites filled with organoclay were apparently higher than that of the nanocomposite filled with MMT. This is attributed to the better filler-matrix interactions between PBS and the organoclay and the better filler dispersion. This is verifiable through the XRD, scanning electron microscopy, and transmission electron microscopy. The addition of PBS-g-MA further improved the mechanical properties. It was also found that our laboratory synthesized organoclay modified with HTAB has provided a better reinforcing efficiency when compared with the commercial octadecylamine-modified organoclay. Besides that the thermal properties of PBS nanocomposites were studied through differential scanning calorimetry. POLYM. ENG. SCI., 2013. (c) 2013 Society of Plastics Engineers