We deposited by the Reothaxial Growth and Thermal Oxidation growth technique thin films of Fe-doped Indium oxide for ozone and NO 2 sensing. SEM and TEM analyses on annealed and as-deposited films showed that Fe doping promotes formation of nanosized core-shell structures, prevents coarsening of the grains and higher stoichiometry is achieved. The effect of iron on sensing behavior towards O 3 is to reduce the optimal working temperature for ozone detection down to 250 C. Iron doping enhances also detection of low NO 2 conentration at 250 C. The interference from reducing gases like CO, ethanol and methanol is negligible at 250 C, and increase at higher working temperatures.