Alkaline water electrolysis by using various oxides was investigated for a compact hydrogen generator. It was found that La0.6Sr0.4CoO3 exhibits high activities to both cathode and anode reactions in water electrolysis and shows good chemical stability. The overpotential for H-2 formation is almost the same with that of Pt. Anodic overpotential of La0.6Sr0.4CoO3 is much smaller than that of Pt. Therefore, by using La0.6Sr0.4CoO3 as an electrode, a Pt-free electrolysis cell for alkaline water electrolysis with high efficiency is realized. Stable electrolysis performance of the cell using La0.6Sr0.4CoO3 for both anode and cathode was sustained over 250 h examined. (C) 2008 The Electrochemical Society.