The electrical conductivity, thermoelectrical, and optical properties of the polyaniline containing boron/double wall carbon nanotubes (CNTs) composites have been investigated. The electrical conductivities of the composites prepared with 1%, 5%, and 8% CNT concentrations at 300 K were found to be 5.31 x 10(-6), 2.72 x 10(-4), and 1.12 x 10(-3) (S/cm), respectively. The thermoelectrical results indicate that all the samples exhibit n-type electrical conductivity. The optical band gaps of the samples were found to be 3.71eV for 0% DWNT, 3.32eV for 1% DWNT, 3.15eV for 5% DWNT, and 3.12 eV for 8% DWNT. The obtained results suggest that the electrical conductivity of PANI-B polymer is improved by DWNT doping. Copyright (c) 2008 John Wiley & Sons, Ltd.