Long living component of photoconductivity after stopping the light irradiation. Persistent photoconductivity(PPC) has been observed in C 6 0 doped poly(3-alkylthiophene) (PAT). PPC increase with increasing irradiation time and also with C 6 0 concentration, tending to saturation. Its temperature dependence of PPC has been also unique. These PPC has been discussed in terms of enhanced photoexcited carrier density in C 6 0 doped PAT and suppressed recombination of primary negative and positive carriers by taking to the stabilization of trapped electron in C 6 0 and defect states in PAT into consideration.