ZrO2:TiO2 hetero-nanofibers composite was synthesized via electrospinning with double jets based on positive and negative polarity electric fields. The hetero-nanofibers were characterized by using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). ZrO2:TiO2 composite shows a netted hetero-nanofibers structure with interleaving of two different diameters nanofibers. Humidity sensors were fabricated based on ZrO2:TiO2 hetero-nanofibers. The impendence of the sensor changed four orders of magnitude from 10(5) to 10(1) k Omega in relative humidity (RH) range of 11 similar to 97% at 25 degrees C. The max humidity hysteresis was around 5% RH, and the response and recovery times were less than 5s and 20s. respectively. The properties of impendence vs. RH at different temperatures were discussed. Overall, the humidity sensor of ZrO2:Ti02 hetero-nanofibers exhibited good sensing characteristics. The humidity sensing mechanism was analyzed via dielectric loss and equivalent circuit. (C) 2011 Elsevier B.V. All rights reserved.