Disclosed are composite particles comprising: (a) conductive polymer particles; and (b) conductive inorganic nanoparticles having a higher conductivity as compared to the conductive polymer, wherein the conductive inorganic nanoparticles are distributed onto the surface of the conductive polymer particles and/or inside the conductive polymer particles. An electrode comprising the composite particles and an electrochemical device including the electrode are also disclosed. When the composite particles comprising a conductive polymer and conductive inorganic nanoparticles uniformly distributed in the conductive polymer are used for forming an electrode, the amount of electrode active material contributing to the capacity of an electrochemical device increases. Thus, the electrochemical device can provide high capacity and improved lifespan characteristics.