Provided are a semiconductor device and a method of fabricating the same. The semiconductor device may include a plurality of unit cells provided on a semiconductor substrate. Each of the unit cells may include a buried insulating pattern buried in the semiconductor substrate, a first active pattern provided on the buried insulating pattern, and a second active pattern provided on the buried insulating pattern and spaced apart from the first active pattern. The buried insulating pattern may define a unit cell region, in which each of the unit cells may be disposed.