Separation of radioactive cations and anions simultaneously is very difficult. A novel Ag2O anchored sodium niobate nanofibers were fabricated to overcome this problem. The nanocomposite showed the desirable performance for simultaneous removal of Sr2+ and I−. It showed the higher adsorption capacity for Sr2+ and I− than other similar materials over a wide pH range. The nanocomposite is easy to separate from waste water after purification due to its fibril morphology.