Effects of titanium dioxide memristor exposure to proton and ion beams are investigated. A memristor model assuming ohmic electronic conduction and linear ionic drift is used for the analysis. Simulations of particle transport suggest that radiation induced oxygen ion/oxygen vacancy pairs can influence the device’s operation by lowering both the mobility of the vacancies and the resistance of the stoichiometric oxide region. These radiation induced changes affect the current-voltage characteristic and state retention ability of the memristor.