Boron neutron capture therapy (BNCT) is a novel cancer treatment modality that can selectively target the tumor without causing excessive radiation damage to the normal tissues. In this project, we developed 2 types of new therapeutic agents for BNCT : cell-penetrating peptides using the protein therapy or nanoparticles, which are effective of delivering cargo into cells, to deliver ^<10>B into the tumor cells as BNCT agents. In both in-vitro studies using the cultured tumor cells and in-vivo studies using tumor-bearing mice, these agents were only observed in the tumor. The results suggest that our systems utilizing peptides or nanoparticles provide an effective means of delivering ^<10>B into tumor cells selectively in BNCT.