A method of fabricating a thin film transistor, in which source and drain electrodes are formed through a solution process, even all stages which include formation of electrodes on a substrate, formation of an insulator layer, and formation of an organic semiconductor layer are conducted through the solution process. In the method, the fabrication is simplified and a fabrication cost is reduced. It is possible to apply the organic thin film transistor to integrated circuits requiring high speed switching because of high charge mobility.