A single‐pole, double‐throw, cutoff‐type ferrite switch has been developed for operation atC‐ andS‐band frequencies. TheC‐band unit is designed for a peak power level of 1 MW with an insertion loss less than 1 dB. Both units display a switching time of 150 &mgr;sec. The device consists essentially of a three‐port waveguide junction with a section of reduced size ferrite‐loaded waveguide at two of the ports. The characteristics of the reduced area sections are such that microwave energy in the frequency range of interest is propagated if no magnetic biasing field is applied. Upon application of the biasing field, the effective permeability of the ferrite is reduced, causing the loaded waveguide to be cut off. The structure is matched so that, if the magnetic field is applied to one section and not the other, a minimum input VSWR is obtained, and there is a maximum transfer of energy to the unbiased port. Switching is accomplished by applying the magnetic biasing field to one ferrite‐loaded section, while at the same time removing the magnetic field from the other. The technique of using cutoff waveguide to create the ``off'' condition provides isolation greater than that obtained by other means, e.g., switching circulators. It is believed that this is the first device of this type to be operated at a truly high power level. High‐power operation has been achieved by the novel approach of operatingabovethe onset threshold for subsidiary resonance absorption. This technique appears promising for use in the development of various high‐power devices in the future.