Conducting poly(3-acetylpyrrole) (PAPy)/multiwalled carbon nanotubes (MWNTs) composites were synthesized by the in situ chemical polymerization of 3-acetylpyrrole (APy) onto MWNTs. The structure and morphology of the PAPy/MWNT composites were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and thermogravimetric analysis. The FTIR results indicated that no chemical reaction occurred between the PAPy and MWNTs, and only the MWNTs served as a template for APy polymerization. FE-SEM and TEM suggested that PAPy was only coated on the surface of the carbon nanotubes, and the thickness of the PAPy coating on each nanotube was dependent on the ratio of APy to MWNTs. The standard four-probe method was used to measure the electrical conductivity of the samples at room temperature, and the results show that the MWNTs enhanced the electrical conductivity of the composites compared to PAPy. In addition, the solution stability of the suspension with the PAPy [or polypyrrole (PPy)]/MWNT composites was investigated; this showed that the dispersion of the PAPy/MWNT composites in ethanol solution was much better than that of the PPy/MWNT composites. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012