Gas sensors based on pure ZnO hollow spheres (ZHSs) and MWCNTs/ZHSs hybrid materials were fabricated. Prepared sensors were examined to detect 320 ppm of target volatile organic compounds including ethanol, methanol, acetone and ether at temperatures ranging from 120 to 380 degrees C, using direct injection in a closed chamber. Results showed that the addition of CNTs to the ZHSs matrix increased significantly the responses of the hybrid sensors compared to the blank sensor. It was found that the addition of 0.1 wt.% of MWCNTs to the ZHSs matrix increased the response of the resulted sensor to the acetone as much as 8.87 times compared to the blank sensor at the same temperature. It was also found that the addition of MWCNTs to the ZHSs matrix decreased the optimum operating temperatures of the hybrid sensors. In addition, mixing the CNTs with ZHSs makes the hybrid sensors to be selective in response to the target volatile organic compounds. The effect of CNTs on the response and recovery times and saturation limits of the sensors were reported and discussed. (C) 2016 Elsevier B.V. All rights reserved.