Provided are a semiconductor memory device whereby generation of dishing during planarization of a peripheral circuit region is suppressed, and a method of fabricating the semiconductor memory device. The semiconductor memory device includes a semiconductor substrate comprising a first active area in a memory cell region and a second active area in a peripheral circuit region; a plurality of first isolation films and a plurality of second isolation films protruding from a surface of the semiconductor substrate and defining the first active area and the second active area, respectively; and at least one polish stopper film formed within the second active area and protruding from the surface of the semiconductor substrate.