An electromagnetic flowmeter comprising a non-conductive body having a central channel, first and second diametrically opposed cavities extending from the channel, and third and fourth cavities positioned, relative to liquid flow through the central channel, upstream and downstream of the first and second cavities, respectively. First and second self-sealing measuring electrodes are respectively positioned in the first and second cavities, and third and fourth self-sealing grounding electrodes are respectively positioned in the third and fourth cavities. Each of the electrodes has a tip and a multiplicity of saw-tooth edges extending outwardly from the periphery of the electrode. Each of the saw-tooth edges has a crest, a face normal to a longitudinal axis of the electrode and extending from the crest to the periphery, and a face at an acute angle to the longitudinal axis of the electrode and extending from the crest to the periphery closer to the tip than where the normal face reaches the periphery. This configuration, in addition to providing a self-sealing effect between the electrodes and the cavities into which the electrodes are inserted, facilitates insertion of the electrodes into the cavities, and hinders withdrawal of the electrodes from the cavities.