Electrochemical behavior of transition metal oxides, Li(x)MO(2) (M = Co, Ni) was examined in all solid state cells using a lithium ion conductive glass, Li3PO4-Li2S-SiS2, as the electrolyte and Li metal as the negative electrode. Complex impedance analysis showed that the electrochemical reaction rate at LixCoO2 electrode was mainly controlled by diffusion for x > 0.95 and by charge transfer for x < 0.95. Coulometric titration showed that these electrode materials had specific capacities of 80-90 mAh/g, coulombic efficiencies of 100%, and equivalent voltages of around 4 V versus Li, so they are promising candidates for positive electrode materials for all solid state lithium batteries.