In this work,a gas sensor is fabricated from polycrystalline nickel cobaltite nano films deposited on transparent substrates by closed-field unbalanced dual-magnetrons (CFUBDM) co-sputtering technique.Two targets of nickel and cobalt are mounted on the cathode of discharge system and co-sputtered by direct current (DC) argon discharge plasma in presence of oxygen as a reactive gas.The total gas pressure is 0.5 mbar and the mixing ratio of Ar:O2 gases is 5∶1.The characterization measurements performed on the prepared films show that their transmittance increases with the incident wavelength,the polycrystalline structure includes 5 crystallographic planes,the average particle size is about 35 nm,the electrical conductivity is linearly increasing with increasing temperature,and the activation energy is about 0.41 eV.These films show high sensitivity to ethanol vapor.