Provided are a method of manufacturing an organic thin film transistor (TFT), the organic TFT manufactured using the method, and a flat panel display device comprising the organic TFT. The method includes: coating a lubricant on a predetermined region of a substrate where an organic semiconductor layer is not to be formed; coating an organic semiconductor layer on the entire substrate; heating the coated substrate to melt the lubricant; and releasing the organic semiconductor layer formed above the predetermined region from the substrate. According to the method, the organic semiconductor layer can be effectively patterned without damaging the substrate and the organic semiconductor material.