Temperature dependent electrical characterization of a composite, made by dispersing single-walled carbon nanotubes (SWNT) in polythiophene (PT) conducting polymer, is performed. Critical temperatures are found by investigating electrical properties and the electrical behaviors of the synthesized systems constitute a good infrastructure for both understanding the intrinsic mechanisms and optimizing new similar synthesizes. The dielectric constant epsilon' of PT/SWNT composite is found to be higher than that of PT overall temperatures and frequencies. Conductivity of PT/SWNT sample jumped to larger values at high temperatures. C) 2007 Elsevier B.V. All rights reserved.