A semiconductor device having a moisture-proof dam and a method of fabricating the same are provided. The semiconductor device includes an interlayer insulating layer provided on a substrate having a fuse region. A fuse guard dam is provided on the interlayer insulating layer to surround the fuse region. A cover insulating layer is provided on the interlayer insulating layer to cover the fuse guard dam and have a fuse window exposing a middle part of the fuse region, and at least two upper extension dams are provided in the cover insulating layer to sequentially surround the fuse region and be connected to the fuse guard dam.