Composites of polyaniline (PANI) and multi-wall carbon nanotubes (MWNT) were synthesized by in-situ polymerization at different multi-wall carbon nanotube contents. The composites were characterized by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and X-ray podwer diffraction (XRD). The results show that a mass of MWNT was enchased into PANI matrix and a bit of MWNT's surface was covered with PANI. There are no covalent interactions between PANI and MWNT. The composites' conductibility was measured by four-point electric conductivity measurement on pellets compressed at 20MPa. It can be confirmed that the composites of carbon nanotubes have a higher conductivity compared to pure PANI. The composites did not have a lower infrared emissivity than pure PANI and the magnitude of infrared emissivity was not influenced by the content of MWNT within the percentage range of MWNT studied.