The radiation chemistry of pertechnetate has been examined in highly alkaline solution. In the presence of selected, organic O- scavengers, radiolysis reduces TcO4- with varying radiation chemical yields, which depend on the reduction potentials of the organic radicals produced during radiolysis. When aminopolycarboxylates are used as O- scavengers, the radiation chemical yield for pertechnetate reduction, G(-TcO4-) is equal to 1/3 G(e(aq)(-)), which strongly implies that the organic radicals produced by the reaction of O- with aminopolycarboxylates are unreactive toward the technetium species present in solution. In the presence of excess nitrate, TcO4- is still efficiently reduced during radiolysis when aminopolycarboxylates are used as O- scavengers. This observation is consistent, with the reduction of TcO4- by NO32-.