A wiring structure in a semiconductor device may include a first insulation layer formed on a substrate, a first contact plug, a capping layer pattern, a second insulation layer and a second contact plug. The first insulation layer has a first opening that exposes a contact region of the substrate. The first contact plug is formed on the contact region to partially fill up the first opening. The capping layer pattern is formed on the first contact plug to fill up the first opening. The second insulation layer is formed on the capping layer pattern and the first insulation layer. The second insulation layer has a second opening passing through the capping layer pattern to expose the first contact plug. The second contact plug is formed on the first contact plug in the second opening. Since the wiring structure includes the capping layer pattern, the wiring structure may prevent a contact failure by preventing chemicals from permeating into the first contact plug.