We present a facile method to prepare helical polyaniline (PANI) microwires or rods guided by poly(acrylic acid) (PAA). The average length and diameter of the helical strands were about 3.5 mu m and 500 nm, respectively. The pitch distance was about 400 nm. The morphology of the helical PANI microwires was affected by the concentration of PAA. As the concentration was decreased to below 0.05 mg/ml. helical wire- or rod-like products were observed. The structure of the helical polyaniline microwires were characterized by means of TEM. SEM, XRD, FTIR and UV-vis spectroscopy. (c) 2005 Elsevier Ltd. All rights reserved.