SnO 2 nanoparticles-reduced graphene oxide (SnO 2 -rGO) nanocomposites have been successfully prepared by a facile method via hydrothermal treatment of aqueous dispersion of GO in the presence of Sn salts. The combined characterizations including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) indicate the successful formation of SnO 2 -rGO nanocomposites. To demonstrate the product on sensing application, gas sensors are fabricated using SnO 2 -rGO nanocomposites as sensing materials and investigated for detection of NO 2 at low operating temperature (50°C). It is found that SnO 2 -rGO nanocomposites exhibit high response of 3.31 at 5ppm NO 2 , which is much higher than that of rGO (1.13), and rapid response, good selectivity and reproducibility. Furthermore, the reason for enhancing sensing performance by addition of SnO 2 nanoparticles has also been discussed.