This paper reports the structural, electrical and thermal properties of the polyaniline doped with ZnO composites. Conducting polymer composites of polyaniline/zinc oxide (PANI/ZnO) have been synthesized by in-situ polymerization of aniline using various compositions (10, 20, 30, 40, 50 wt %) of ZnO in PANI using ammonium persulphate as an oxidant. The amorphous nature of the composites has been ascertained by the X-ray diffraction. Fourier Transform Infrared (FTIR) spectroscopy confirms the interaction between PANI and dopant. Thermal stability of polymer composites has been analyzed by TGA and corresponding thermal kinetic parameters were calculated using Horowitz-Metzger method. Thermal analysis shows higher thermal stability of PANI/ZnO composites than pure PANI. The surface morphology of these composites was analyzed with Scanning Electron Microscopy (SEM), which also confirms the presence of ZnO in the composites. The dc conductivity behaviour of these composites has also been investigated as a function of temperature and concentration in the temperature range 313-393 K and the results were compared with pure PANI. The dc electrical conductivity of PANI/ZnO composites decreased as the ZnO content increased in PANI but increased with the increase in temperature