Disclosed are a semiconductor memory device and a method of fabricating the same. The device may include a first substrate comprising a cell array region, a first interlayer insulating layer covering the first substrate, a second substrate disposed on the first interlayer insulating layer, the second substrate including a core region electrically connected to the cell array region, a first adhesive insulating layer interposed between the first interlayer insulating layer and the second substrate, and contact plugs penetrating the second substrate, the first adhesive insulating layer, and the first interlayer insulating layer and electrically connecting the cell array region with the core region.