A method for monitoring the status of a vibronic sensor for determining and/or monitoring at least one process variable of a medium in a container, with at least one sensor unit with a unit that can mechanically oscillate, comprising the following process steps: - Causing the unit that can mechanically oscillate to mechanically oscillate using an excitation signal (U A) and receiving the mechanical oscillations in the form of a received signal (U E), - Determining a measured value for the amplitude and a measured value for the frequency (f) of the received signal (U E), - Comparing the measured values for the amplitude and for the frequency (f) with a reference value for the amplitude (A ref) and the frequency (f ref), respectively, and - Determining a status indicator from the comparison, characterized in that in the event that no measured value can be determined for the amplitude, and the measured value for the frequency (f) is less than the reference value (f ref), it is concluded that there is corrosion and/or abrasion on the oscillating rods (8a, 8b) and/or a hard deposit in the area of the membrane, and in the event that the deviation between the measured value and reference value (A ref) for the amplitude is less than a pre specifiable limit value, and the measured value for the frequency (f) is less than the reference value (f ref), it is concluded that there is a hard deposit in the area of the oscillating rods (8a, 8b) and/or corrosion and/or abrasion in the area of the membrane, and in the event that the measured value for the amplitude is less than the reference value (A ref), and that the deviation between the measured value (f) and reference value (f ref) for the frequency is less than a prespecifiable limit value, it is concluded that there is a defect in the area of the drive/receiving unit, in particular in the area of at least one piezoelectric element of the drive/receiving unit, and/or a defect in the area of the electronics. - Causing the unit that can mechanically oscillate to mechanically oscillate using an excitation signal (U A) and receiving the mechanical oscillations in the form of a received signal (U E), - Determining a measured value for the amplitude and a measured value for the frequency (f) of the received signal (U E), - Comparing the measured values for the amplitude and for the frequency (f) with a reference value for the amplitude (A ref) and the frequency (f ref), respectively, and - Determining a status indicator from the comparison, in the event that no measured value can be determined for the amplitude, and the measured value for the frequency (f) is less than the reference value (f ref), it is concluded that there is corrosion and/or abrasion on the oscillating rods (8a, 8b) and/or a hard deposit in the area of the membrane, and in the event that the deviation between the measured value and reference value (A ref) for the amplitude is less than a pre specifiable limit value, and the measured value for the frequency (f) is less than the reference value (f ref), it is concluded that there is a hard deposit in the area of the oscillating rods (8a, 8b) and/or corrosion and/or abrasion in the area of the membrane, and in the event that the measured value for the amplitude is less than the reference value (A ref), and that the deviation between the measured value (f) and reference value (f ref) for the frequency is less than a prespecifiable limit value, it is concluded that there is a defect in the area of the drive/receiving unit, in particular in the area of at least one piezoelectric element of the drive/receiving unit, and/or a defect in the area of the electronics.