Addition of few-layer graphene and graphite to poly(3,4-ethylenedioxy-thiophene):poly (styrenesulfonate) (PEDOT:PSS) is of great technological relevance for a host of applications, including electrodes for organic solar cells and the development of solution-processable conducting inks with improved thermal properties. In this paper we investigate the optical, electrical, morphological and thermal properties of nanocomposites formed by the incorporation of PEDOT: PSS into carbon-based thin films in which the thermal properties approach those of graphene. The properties of these nanocomposite thin films can be understood in the framework of a two-layer model, with a bottom layer formed by an effective medium of PEDOT: PSS and graphene-like flakes and a top layer of pure PEDOT: PSS. Strong dependence on the film thickness and morphology was found for all of the thermophysical properties we studied. We show a strong improvement in thermal conductivity due to the addition of graphene-like material to PEDOT:PSS. (C) 2013 Elsevier B.V. All rights reserved.