Nowadays, thermoelectric (TE) materials have gained considerable attention due to their unique ability to directly convert waste heat to electricity and vice versa. For a long time, researchers have mainly focused on developing high-performance inorganic TE materials, e.g., Bi-Te, Pb-Te, and Si-Ge based alloys, etc. However, inorganic TE materials have various disadvantages, such as high-cost, heavy metal contamination, as well as relatively poor processability, etc. Compared to inorganic TE materials, poly(3,4-ethylenedioxythiophene) (PEDOT) has great potential to be used for TE materials, due to its low thermal conductivity, low-cost, and low-density, etc. Therefore, more and more attention has been focused on the preparation and TE properties of PEDOT and PEDOT based nanocomposites, especially one-dimensional (1-D) PEDOT and 1-D PEDOT based nanocomposites, due to 1-D nanostructures always have enhanced TE properties. This article presents an overview of the synthesis of PEDOT nanoparticles, 1-D PEDOT nanostructures and their corresponding nanocomposites, as well as TE properties. (C) 2017 Elsevier B.V. All rights reserved.