Abstract: A magnetic stimulator for neuro-muscular tissue uses a stimulating coil and generates a succession of electrical discharge pulses from the coil to produce magnetic pulses which induce electrical signals in the tissue. The coil has at least one set of generally circular turns, and is disposed within a casing connected to a conduit through which extend cables for the supply of electrical power to the coil. The conduit and casing allow for the flow of gaseous coolant around and over exposed surfaces of the coil, though the casing and along the conduit.