Abstract: An RF excited metal waveguide laser wherein one of the two opposed electrodes forming the discharge region has its top surface thereof formed as a waveguide thus eliminating the dielectric sidewalls used in prior art metal waveguide lasers. In the preferred embodiment, an enclosure having metal sidewalls and bottom has one of the electrodes attached thereto and the opposite electrode is attached to a dielectric cover on the enclosure. The laser gas can be circulated through the entire enclosure to aid in the cooling of the electrodes. The preferred shape of the waveguide electrode is with a longitudinal and transverse concave radius of curvature.