An electrochemical sensor for determining the oxygen content of exhaust gases comprises a sensor stone made of an ionconducting solid electrolyte in the form of a tube closed at one end, an inner electrode and an outer electrode. The outer electrode, which is arranged on the outer surface of the sensor stone, has a connection-side conducting track with a covering layer. The sensor also has a ceramic protective coating and a metal gasket which seals the reference chamber from the exhaust gas chamber and establishes an electrical contact with the housing in which the sensor is inserted. The covering layer which covers the conducting track is extends on the reference side of the sensor stone below the metal gasket. As a result, the service life of the sensor is appreciably prolonged.
