An oxygen generating electrode has on a conductive substrate a first layer of metallic platinum and tantalum oxide containing 80-99 mol% of Ta and 20-1 mol% of Pt, a second layer of iridium oxide and tantalum oxide containing 80-99.9 mol% of Ir and 20-0.1 mol% of Ta, and preferably a third layer of iridium oxide and tantalum oxide containing 40-79.9 mol% of Ir and 60-20.1 mol% of Ta. In another embodiment, the first layer consists of iridium oxide and tantalum oxide and contains 14-8.4 mol% of Ir and 86-91.6 mol% of Ta. The electrode, when used as an anode in electrolysis with concomitant oxygen generation, can be used for an extended period at a low bath voltage. It is adapted for electrolysis at a high current density of more than 100 A/cm.sup.2 since it maintains mechanical strength and has a long effective life. It experiences a minimal change of oxygen overvoltage with time.