New layered perovskite compounds, AgLaTa2O7 and AgCa2Ta3O10, have been synthesized by an ion-exchange reaction from parent compounds, RbLaTa2O7 and RbCa2Ta3O10. The crystal structures of silver ion-exchanged compounds were determined by the Rietveld analysis for powder XRD patterns. These compounds, which are probably metastable, could only be obtained by the ion-exchange reaction. The relatively high ionic conductivities attributed to the interlayer silver ions were observed at high temperatures.