A individually position-addressable large-scale-aligned Cu nanofiber (NF) array is fabricated using electro-hydrodynamic nanowire printing. The printed single-stranded Cu NF has a diameter of about 710 nm and a resistivity of 14.1 mu Omega cm and is effectively used as source/drain nanoelectrode in pentacene transistors, which show a 25-fold increased hole mobility than that of a device with Cu thin-film electrodes.