Organic fibers that can function as electronic components such as batteries, sensors, and actuators are exciting prospects for new textile technologies known as "smart fabrics" or "e-textiles." Conducting polymer materials are ideal candidates for such fibers as a result of their good electronic conductivity and mechanical properties and their electrochemical activity. The latter allows the polymer to act as a battery or supercapacitor electrode, to respond to its chemical surroundings as a sensor and to change properties (e.g., color, conductivity, and stiffness) and size when oxidized or reduced. Developing these useful materials into fiber forms has involved wet spinning of soluble forms of polyaniline, polypyrrole, and polythiophene. Both structural modification to the base monomer and the use of solubilizing dopants have been used to render the polymer soluble. In some cases, the addition of carbon nanotubes to the spinning solution has been used to produce composite fibers with improved mechanical and electrical properties. These fibers have been evaluated for applications including biomechanical sensors and artificial muscles. The main current limitation in the further development of conducting polymer fibers for textiles processing is their low toughness.