Metal-insulator-semiconductor field effect transistor (MISFET) using poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) as an active channel was fabricated by multiple line patterning, one of the most simple, rapid, and inexpensive methods capable of making patterns of conducting polymers, insulators, and metals using a standard laser printer. The MISFET operated both in the depletion and enhancement modes in response to positive and negative gate voltages, respectively, where the gate current was crucial to the performance of the device. Furthermore, a novel device, metal-semi conductor field effect transistor (MESFET) using a Schottky barrier formed at the interface between aluminum and PEDOT/PSS instead of the polymer insulator, was fabricated.