Amorphous In-O thin films with a thickness of ~0.1 μm were produced by thermal evaporation of indium oxide powder in a vacuum of 10 - 5 -5 x 10 - 4 Torr onto glass substrates at room temperature. The films had conductivities of either σ 0 = 10 - 3 -10 - 2 (Ω cm) - 1 or 0.1-1 (Ω cm) - 1 . An electric field of 6 x 10 2 -3 x 10 4 V/m with its consequent transverse current injection (TCI) was applied parallel to the films for 15-400 min in vacuum after deposition, and the conductivity of films was measured as a function of the time for different applied fields. The current injection increased the film conductivity by a factor of 4-6 for the films with the lower σ 0 and by a factor of 2-3 for the films with higher σ 0 . Subsequent TCI in air restored the previous conductivity of the high σ 0 films, while subsequent TCI in helium or nitrogen had no effect. The as-deposited films are suspected to consist of high conductivity islets in a low conductivity matrix. The conductivity increase is explained by TCI induced outgassing of O 2 , leading to an increased carrier concentration at the cathodic extremity of the high conductivity regions, which decreases the distance between high conductivity regions and ultimately connects them together.