A proposed new electrode for measurement of foetal auditory brain stem response (ABR) is presented, the structure of which resembles a syringe needle. It can be placed subdermally in the head of the guinea pig foetus through the wall of the maternal abdomen. In the anterior end of the electrode a special device similar to a hook is situated. The device may be controlled from outside the maternal abdomen. In comparison with the placement of electrodes through the surgical incision, its placement is simple and injury to tissue is relatively small. It is not only firmly fixed in the subcutaneous tissue of the foetus to satisfy the need for the measurement of foetal ABR, but is easily removed from the foetus. To our knowledge no other similar electrode has been reported.