The design of an inductive power system is investigated in order to determine the relative benefits provided by the inclusion of a magnetic core in the receiver coil. Both transmitter and receiver coils are chosen to have dimensions similar to those used in many biomedical devices. It is found that while a magnetic core provides enhanced coupling, the operating frequency is limited by losses in the magnetic material. Consequently, the performance of air-core coils is shown to match that of coils with magnetic cores when operated at a higher frequency. Work is ongoing to consider the effects of other limitations imposed by biomedical environments.