A method and device for forming a signal relating to a temperature in the exhaust system of an internal combustion engine. The method can be used, for example, to form a signal for the exhaust gas temperature upstream of the catalytic converter, a signal for the temperature in the catalytic converter, or a signal for the temperature downstream of the catalytic converter. The first step is to form a signal for a steady-state exhaust gas temperature as a function of at least one operating characteristic of the internal combustion engine. This signal can be subjected to a series of corrections in order to take into account parameters such as the efficiency of the internal combustion engine, the air/fuel ratio, the temperature of the intake air, the mixture flow rate, the vehicle speed, a possibly activated cylinder cutout, and the presence of condensed water in the exhaust system.