A magnetic-inductive flowmeter includes a measuring tube for carrying an electrically conductive medium, a magnetic field generator for generating a magnetic field passing through the medium, two electrodes for tapping a measuring voltage induced in the medium, a ground element electrically connected to the medium, and an evaluation unit. The electrodes are connected to the evaluation unit via electrode lines. The ground element is connected to the evaluation unit via a first ground line for potential equalization between the medium and a reference potential of the evaluation unit. The ground element is connected to the evaluation unit at least indirectly via a second ground line. The first and second ground lines are part of a monitoring circuit for monitoring the connection between the ground element and the evaluation unit. The evaluation unit is designed such that it monitors the connection between the ground element and the evaluation unit.