Soft, flexible polymer-based bioelectronics are a promising approach to minimize the chronic inflammatory reactions associated with metallic devices, impairing long-term device reliability and functionality. This work demonstrates the fabrication of conductive elastomers (CEs) consisting of chemically synthesized poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires embedded within a polyurethane (PU) elastomeric matrix, resulting in soft and flexible, fully polymeric electrode materials. Increasing PEDOT nanowire loadings resulted in an improvement in electrochemical properties and conductivity, an increased Young's modulus and reduced strain at failure. Nanowire CEs were also found to have significantly improved electrochemical performance compared to one of the standard electrode materials, platinum (Pt). Indirect in vitro cytocompatibility test was carried out to investigate the effect of leachable substances from the CE on primary rodent cells. Nanowire CEs provide a promising alternative to metals for the fabrication of soft bioelectronics.