Composites of polyaniline (PANI) nanorods and multiwalled carbon nanotubes (MWNTs) coated with PANI were prepared by in situ polymerization with perchloric acid as a dopant. Transmission electron microscopy images showed that the coexisting composites of PANI nanorods and MWNTs coated with PANI were formed at low MWNT contents. The interaction between MWNTs and PANI was proved by Fourier transform infrared and ultraviolet-visible spectra. The electrical conductivity of a dedoped PANI/MWNT composite with a 16.3 wt % concentration of MWNTs reached 3.0 x 10(-3) S/cm, which was 6 orders of magnitude higher than that of decloped PANI nanorods. The results also showed that coexisting composites of PANI nanorods and MWNTs coated with PANI had high electrochemical activity and good cyclic stability. (C) 2007 Wiley Periodicals, Inc. J Appl Polym Sci 106: 4241-4247, 2007