In a method of controlling a sensor for determining an oxygen concentration in a gas mixture, in particular in the exhaust gas of internal combustion engines, a detection voltage supplied by a Nernst measurement cell and corresponding to the oxygen concentration is transformed by a circuit arrangement into a pump voltage for a pump cell, and an anodic or cathodic limit current flows over the pump cell, depending on the oxygen content of the gas mixture. In stable operation of the sensor, during which an anodic limit current flows for a selectable period of time, the pump cell and/or the Nernst measurement cell receives at least one voltage pulse supplied independently by the measured detection voltage or the pump current thus established, so that the sensor is depolarized.