Conductive polypyrrole nanofibers with diameters in the range of about 70-300 nm were obtained using electrospinning processes. The conductive nanofibers had well-defined morphology and physical stability. Two methods were employed. Electrospun nanofibers were prepared from a solution mixture of polypyrrole (PPy), and poly(ethylene oxide) (PEO) acted as a carrier in order to improve PPy processability. Both the electrical conductivity and the average diameter of PPy nanofibers call be controlled with the ratio of PPy[PEO content. In addition, pure (without carrier) polypyrrole nanofibers were also able to be formed by electrospinning organic solvent soluble polypyrrole, [(PPy3)(+) (DEHS)(-)](x), prepared using the functional doping agent di(2-ethylhexyl) sulfosuccinate sodium salt (NaDEHS) [Jang KS, Lee H, Moon B. Synth Met 2004; 143:289-94. 124]]. Electrospun blends of sulfonic acid (SO3H)-bearing water soluble polypyrrole, [PPy(SO3H)-DEHS], with PEO acting as a carrier, are also reported. The factors that facilitate the formation of electrical conduction paths through the electrospun nanofiber segments are discussed. (c) 2006 Elsevier Ltd. All rights reserved.