A method of forming a conductive pattern in which the conductive pattern can be easily formed at a low temperature without a photolithography process by forming the conductive pattern using a laser ablation method and an inkjet method, an organic thin film transistor manufactured using the method, and a method of manufacturing the organic thin film transistor. The method of forming a conductive pattern in a flat panel display device includes preparing a base member, forming a groove having the same shape as the conductive pattern in the base member, and forming the conductive pattern by applying a conductive material into the groove. The base member has one of a structure including a plastic substrate having the groove and a structure including a substrate and an insulating layer which is arranged on the substrate and which has the groove.