We present the successful prototype development results of a novel compact rotating‐wave electron beam accelerator (RWA). The RWA uses a single cylindrical cavity holding a transverse‐magnetic resonant mode in combination with an axial static magnetic field to accelerate electrons to higher energies. With approximately 80 kilowatts of microwave power fed into a C‐band cavity, we have been able to successfully accelerate a 3 keV electron beam to ∼760 keV. The compact RWA accelerator could be the basis for a new class of compact and affordable 1–10 MeV microwave accelerators for military, medical and industrial applications. © 2003 American Institute of Physics