The oxide bronzes, delta -NayAg0.70-yV2O5, were prepared both by solid stare and ion-exchange reactions, and their lithium insertion/extraction behaviors were examined. Single phase oxide bronzes were obtained at 0 less than or equal to y less than or equal to 0.2 by the solid state reaction and at 0 less than or equal to y less than or equal to 0.5 by the ion-exchange reaction. Reduction of silver(I) in the lithium insertion reaction occurred in succession to the reduction of vanadium(V) to vanadium(IV) up to V-IV/V-V = 1. Reversible insertion/extraction of lithium without changing the layer structure occurred when the total amount of interlayer cations was two in the formula unit, almost independent of the content of sodium ions in the interlayer