CeO 2 -doped ZnO nanostructures, with different Ce/Zn ratios, were synthesized via a very fast microwave-assisted method using zinc acetate dihydrate and cerium nitrate as starting materials and water as solvent. The samples were characterized via SEM, EDX, XRD, and BET analyses. Gas sensitivity of the fabricated sensor was studied for selective detection of ethanol in presence of CO and CH 4 and effect of CeO 2 with different concentrations as a dopant was investigated. 5wt% CeO 2 doped sample was shown to improve the sensor response to 500ppm ethanol with high selectivity in presence of CO and CH 4 . Furthermore presence of ceria reduced the recovery time of the sensor significantly. The CeO 2 -doped ZnO may be considered a promising sensing material for selective detection of ethanol.