Abstract: A flat transmission wire is provided which includes a first insulating or dielectric film, a transmission layer formed on at least one surface of the first insulating or dielectric film so as to transmit electrical signals therethrough, a second insulating or dielectric film formed on one surface of the transmission layer, and a functional layer formed on one surface of the second insulating or dielectric film. Further provided are methods for fabricating flat transmission wires which enable the formation of uniform and fine transmission line patterns, and are environmental friendly, as compared to deposition-based methods.