A method of fabricating semiconductor devices having metal gate electrodes includes forming an insulating layer on a semiconductor substrate having a first region and a second region. The insulating layer is formed to include an interlayer insulating layer and a gate insulation layer. The interlayer insulating layer has first and second grooves respectively disposed in the first and second regions, and the gate insulation layer covers at least bottom surfaces of the first and second grooves. A laminated metal layer is formed on the substrate having the insulating layer. A planarization layer having non-photo sensitivity is formed on the laminated metal layer. The planarization layer in the first region is selectively removed using a dry etching process to expose the laminated metal layer in the first region and to form a planarization layer pattern covering the laminated metal layer in the second region.