In this study, indium oxide (In₂O₃) hollow nanofibers were synthesized through a two-step process. In₂O₃solid nanofibers were prepared by electrospinning, and 10% HNO₃was used to corrode these nanofibers to obtain In₂O₃hollow nanofibers. Moreover, the effects of corrosion on the morphology and acetone-sensing properties of In₂O₃nanofibers were investigated. In₂O₃nanofibers that were corroded for 2 h displayed hollow structures and exhibited a high response (resistance ratio) of 151 to 5 ppm of acetone at 300℃. The minimum detection limit was 20 ppb. The hollow In₂O₃nanofibers also exhibited high selectivity to acetone along with negligible cross-responses to interference gases at 300℃, These gases include NO_2,H₂, CO, benzene, p-xylene, and toluene. The strong response to acetone was attributed to the enhanced accessibility of gas for gas-sensing reactions due to the hollow morphology.