Bismuth telluride (Bi2Te3) nanorods and polyaniline (PANI) nanoparticles have been synthesized by employing solvothermal and chemical oxidative processes, respectively. Nanocomposites, comprising structurally ordered PANI preferentially grown along the surface of a Bi 2Te3 nanorods template, are synthesized using in situ polymerization. X-ray powder diffraction, UV-vis and Raman spectral analysis confirm the highly ordered chain structure of PANI on Bi2Te3 nanorods, leading to a higher extent of doping, higher chain mobility and enhancement of the thermoelectric performance. Above 380 K, the PANI-Bi2Te 3 nanocomposite with a core-shell/cable-like structure exhibits a higher thermoelectric power factor than either pure PANI or Bi 2Te3. At room temperature the thermal conductivity of the composite is lower than that of its pure constituents, due to selective phonon scattering by the nanointerfaces designed in the PANI-Bi2Te 3 nanocable structures. The figure of merit of the nanocomposite at room temperature is comparable to the values reported in the literature for bulk polymer-based composite thermoelectric materials. © 2013 IOP Publishing Ltd.