Composites of high-molecular-weight polyaniline (PANI) and single-walled carbon nanotubes as well as composites of PANI and multiwalled carbon nanotubes of various weight percentages were prepared using solution processing. The integration and distribution of the carbon nanotubes (CNTs) in the PANI matrix were investigated by various characterization methods. CNT distribution was evaluated using scanning electron microscopy, while CNT dispersion and alignment were characterized by transmission electron microscopy. The specific gravity of the composite material was measured using a density gradient column, which indicates how well the nanotubes are integrated into the polymer matrix. Results indicate that effective integration and distribution of CNTs into a PANI matrix can be achieved with solution processing for composites containing between 1 and 5% CNTs by weight. (c) 2007 The Electrochemical Study.