An electromagnetic flowmeter having a measuring tube, at least one magnetic device and at least two electrodes. The measuring tube having an inlet section with an inlet section terminal cross section, an outlet section with an outlet section terminal cross section, a recess formed between the inlet section and the outlet section with a recess cross section that is wider than the inlet section terminal cross section and the outlet section terminal cross section, and an internal coating positioned in the recess. The layer thickness of the internal coating is chosen to be appropriately thick in order to guarantee electrical insulation and to arrange the internal coating in the recess such that it is protected from damage by flowing measurement fluid.