Activated carbon fibers (ACFs) composed of a nano-graphite disordered network have huge specific surface areas ranging 1000-3000m(2)g(-1). The electronic states of iodine adsorbed in ACFs were investigated by I-129 Mossbauer spectroscopy with a focus on charge transfer from nano-graphite to iodine. The observed spectra consisting of five different quadrupole octets demonstrate the coexistence of I-3(-) ion and I-2 molecule in micropores. This fact implies that I-3(-) ions are produced as a result of charge transfer from nano-graphite to iodine. The estimated charge transfer rate on the basis of the ratio of generated I-3(-) is in good agreement with the previous results obtained by magnetic susceptibility.