A device and a method for determining and/or monitoring at least one process variable of a medium include a sensor unit having a mechanically oscillatable unit, at least a first piezoelectric element, a temperature detection unit for determining and/or monitoring a temperature of the medium and an electronics unit. The device is embodied to excite the mechanically oscillatable unit by means of an excitation signal such that mechanical oscillations are executed, to receive mechanical oscillations of the oscillatable unit and convert them into a first received signal, to transmit a transmitted signal and to receive a second received signal. The electronics unit is embodied, based on the first and/or second received signal, to determine the at least one process variable and, based on a third received signal received from the temperature detection unit, to determine the temperature of the medium.