A liquid crystal display device and a fabricating method thereof for simplifying a process are disclosed. In the method of fabricating the liquid crystal display device, a first conductive pattern group including a gate line and a gate electrode, a common line and a common electrode, a pixel electrode and a pad in a multiple conductive layer having a stepwise shape including a transparent conductive layer is formed on a substrate by a first mask process. An insulating film and a semiconductor layer including a plurality of contact holes are formed on the first mask pattern group by a second mask process. A second pattern group including a data line, a source electrode and a drain electrode is formed on the semiconductor layer and the semiconductor layer is patterned, and an active layer is exposed between the source electrode and the drain electrode by a third mask process.