A method for the diagnosis of an exhaust gas recirculation system in an internal combustion engine, including providing a pressure difference reading, which gives a pressure difference in an air supply section of the internal combustion engine or a pressure difference over the exhaust gas recirculation system; determining a pressure difference reference value as a function of one or more operating variables of the internal combustion engine; and detecting a fault in the exhaust gas recirculation system as a function of the pressure difference reading and of the pressure difference reference value.