Alkaline polymer gel electrolyte was prepared from potassium salt of cross-linked poly(acrylic acid) and KOH aqueous solution in order to investigate the applicability of the polymer gel electrolyte to alkaline secondary batteries such as nickel/metal hydride (Ni/MH) battery. The polymer gel electrolyte was found to have high ionic conductivity and wide potential window almost comparable to the KOH aqueous solution over the wide ranges of KOH concentration and temperature. An experimental Ni/MH cell was assembled using polymer gel electrolyte and its charge-discharge and capacity retention characteristics were tested. The cell using the polymer gel electrolyte exhibited somewhat better charge-discharge and capacity retention characteristics at 25 degreesC compared with a similar type of cell assembled using KOH aqueous solution.