A method of fabricating a polysilicon LCD device includes forming an active layer on a substrate, forming a first insulating layer having a first thickness and a second insulating layer having a second thickness sequentially on the active layer, forming a photoresist on the second insulating layer, ashing the photoresist, etching first portions of the first thickness of the first insulating layer corresponding to the source and drain electrode regions and the reduced second thickness of the second insulating layer within the first regions to expose source and drain regions of the active layer corresponding to the source and drain electrode regions, and etching a second portion of the second thickness of the second insulating layer to expose a portion of the first insulating layer corresponding to a gate electrode region, forming a gate electrode, a source electrode, and a drain electrode simultaneously on the second insulating layer, forming a passivation layer on the gate electrode, the source electrode, and the drain electrode, and forming a pixel electrode on the passivation layer.