An electrode for medical applications is provided with a PtIr coating which is at least partly porous. The coating contains more than 20% iridium by weight and at least 100 ppm Pt. The coated areas of the electrode exhibit an electrochemical capacitance of more than 5 mF/cm.sup.2 in physiological saline solution at 37.degree. C. and a measurement frequency of 100 mHz. A sputter process is suitable for this purpose, in which a porous platinum-iridium layer is deposited on the electrode by simultaneously sputtering at least one iridium target and at least one platinum target.