||Thin film transistors (TFTs) based on amorphous oxide semiconductors have emerged as a promising technology, particularly for active-matrix TFT based backplane due to the superior electrical performances, when compared with the conventional amorphous silicon and polycrystalline silicon TFTs, respectively. In fact, several research groups have already presented working devices with remarkable electrical and optical properties based on gallium-indium-zinc oxide (GIZO) materials. Most of these TFTs use indium-tin oxide (ITO) as the material for source/drain electrodes. This presentation focuses on the investigation of different electrodes to replace ITO in GIZO based TFTs. We discuss the source/drain series resistances and their effect on TFT performance. Effective contact resistances between GIZO semiconductor and various metallic electrodes, Al, Ti, Cu, Mo, were examined. The source/drain layers were patterned by lift-off method, and the transistors had a fixed width of 100 ㎛, whereas the channel length was changed between 10 and 50 ㎛. The intrinsic TFT parameters are extracted by the transmission line method (TLM) using a series of TFTs with different channel lengths measured at a low source/drain voltage. Concerning the different source/drain materials, Cu led to the highest intrinsic mobility and the lowest effective contact resistance for all the tested electrodes. For high gate voltage, effective contact resistance started to saturate at a minimum value.