Abstract: An electrode for an arc discharge lamp includes a porous sintered body of tungsten impregnated with a mixture of alkaline earth oxides and a metal oxide. The alkaline earth materials may be oxides of barium and calcium, and the metal oxide may be aluminum oxide. The body is brazed or welded to the end of a high melting point refractory metal support of tungsten or molybdenum. Two identical electrodes are used as the cathodes of a long arc alternating current type xenon lamp and one such electrode provides the cathode of a short arc direct current xenon lamp. The structure and materials provide greater efficiency and extended life under continuous operating conditions.