A novel humidity sensing composite was synthesized using polythiophene (PTh) and graphene oxide by chemical oxidation process. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and investigations on humidity sensing were used to characterize the samples. XRD pattern of PTh demonstrated that it is amorphous in nature. The flaky character and more compact structure of composites were both confirmed by scanning electron microscopy. These findings show that the thiophene monomer successfully polymerized on graphene's surface. Polythiophene/graphene composites were studied for their humidity sensing performance in the relative humidity (RH) range of 11% - 97%.