Organic TFTs having uniform characteristics and a flat panel display having the organic TFT, wherein the organic TFTs include an organic semiconductor layer formed by spin coating are disclosed. One embodiment of the organic TFT includes: a substrate, a gate electrode disposed on the substrate, a gate insulating film covering the gate electrode, an organic semiconductor layer disposed on the gate insulating film, and a source electrode and a drain electrode that contact the organic semiconductor layer, wherein a plurality of protrusion parts is formed on the gate insulating film and the protrusion parts extend toward the drain electrode from the source electrode.