A medical electrode and skin preparation device is adapted to be secured to the skin and is designed to prepare the skin by penetration of the epidermal layer of the skin in contact with the electrical conductor of the electrode after the electrode is secured in place on the skin. The electrode includes abrading member associated with electrical conductor capable of transmitting biopotential events for recording, with the electrical conductor retained by a collar and adhesive-coated pad securing the electrode to the skin of the patient. The abrading member in contact with the skin is movable relative to the skin of the patient and collar by an applicator gun to penetrate the epidermal layer of skin after the electrode is placed on the skin. Uniform skin preparation achieved by the electrode and applicator gun minimizes motion artifacts arising from skin potential variations.