In this study, TiO2 films were deposited on FTO (fluorine-doped tin oxide)/glass substrate by radio frequency magnetron sputtering. Amorphous and anatase structure of TiO2 were achieved without and with thermal process, respectively. Further, TiO2-based thin-film transistors (TFTs) with different structure were fabricated. After the electrical characteristics measurement, it was found that the amorphous TiO2 TFTs can be operated in the enhancement mode with a threshold voltage of 3.8 V. It was also found that the field-effect mobility and on/off current of the TiO2 TFT with amorphous channel layer were 0.087 cm(2) V-1 s(-1) and 10(3), respectively. On the other hand, the TiO2 TFTs with anatase structure were also tested. It was found that the anatase TiO2 TFTs have the lower threshold voltage of 2.3 V than amorphous one. Besides, it was also found that the field effect mobility and on/off current ratio of the anatase TiO2 TFTs were both increased to 10.7 cm(2) V-1 s(-1) and 10(4), respectively. In other words, the performance of TiO2 TFTs was related to the structure of the channel layer. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3561271] All rights reserved.