U ndoped and nickel doped titanium oxide thin films were fabricated by spray pyrolysis by using a solution of titanium tetrachloride and ethyl alcohol. The films have been deposited on heated quartz and silicon substrates at 623 K. After annealing for 120 min at 823 K, the initially amorphous films became polycrystalline with a predominant anatase structure and average crystallite sizes depending on dopant (Ni) concentration. AFM results show that by the addition of the Ni to TiO2 thin films they become smooth. Electrical properties have been studied by means of electrical resistivity and Hall effect measurements. The experimental result shows that nickel doping of titanium oxide thin films improve the sensor element sensitivity to NH3 gas. The influence of variation of Ni concentration on NH3 sensitivity of thin film sensor elements was investigated in this work. It looks promising to use the inexpensive nickel-doped titanium oxed thin films obtained by spray pyrolysis in smart gas sensing devices that are able to recognize gas species in low concentration.