The interfacial resistances of LixC6/GPC/LixMn2O4 cells with glass-polymer composite (GPC) electrolytes have been characterized using in-situ four-probe measurements during cycling. The evolution of impedance spectra of the cells shows that the kinetic stability of the GPC electrolyte against LixC6 and LixMn2O4 electrodes is reasonably good, although there is an initial increase in interfacial resistances. The resistance of a LixMn2O4/GPC interface increases from 370 Ohm as prepared (in the fully discharged state) to 740 Ohm after first cycle and then remains constant up to 80 cycles. The resistance of a GPC/LixC6 interface typically increases from an initial value of 380 Ohm (as prepared) to 1020 Ohm after 50 cycles. The interfacial resistances then stay relatively constant during cycling up to about 80 cycles. The observed discharge capacity fading of the positive electrode (LixMn2O4) is about 8% after 80 cycles.