In a semiconductor device having line type active regions and a method of fabricating the semiconductor device, the semiconductor device includes a device isolation layer which defines the line type active regions in a in a semiconductor substrate. Gate electrodes which are parallel to each other and intersect the line type active regions are disposed over the semiconductor substrate. Here, the gate electrodes include both a device gate electrode and a recessed device isolation gate electrode. Alternatively, each of the gate electrodes is constituted of a device gate electrode and a plan type device isolation gate electrode, and a width of the plan type device isolation gate electrode greater than a width of the device gate electrode.