A method for detecting plugging of a measuring tube. Heat is supplied to a medium conveyed in a first measuring tube by means of at least one heating element, or heat is removed from the medium conveyed in a first measuring tube by means of at least one cooling element. At least one temperature sensor, which is thermally coupled to the medium conveyed in the first measuring tube, temperature is registered. Additionally, a first comparison variable, which is characteristic for heat transport by the medium in the first measuring tube, is determined based on the supplying of heat or removing of heat, as well as on the temperature registering, and this comparison variable is compared with a reference variable. Plugging of at least one measuring tube of the measuring transducer is detected if the first comparison variable deviates from the reference variable by more than a limit value.