Thin film samples of In 2 Se 3 were prepared from synthesized polycrystalline In 2 Se 3 by a thermal evaporation technique. X-ray analysis show that the synthesized material has α-phase structure, while the as-deposited films have an amorphous structure. The films have β-phase structure after annealing at temperature 523 K. The conduction activation energy (E σ ) of the as-deposited samples, as obtained from the temperature dependence of the electrical conductivity, is 0.391 eV. The obtained value of E σ was explained according to a previously postulated band structure of the investigated material.The electrical conductivity of the investigated samples behaves differently with time after annealing at different elevated temperatures. On one hand, E σ decreased for samples after annealing at 423 and 473 K to 0.313 and 0.262 eV respectively; this may be due to the increase of the degree of ordering in the investigated compound with annealing. On the other hand, E σ increased for samples after annealing at 523 K to 0. 787 eV; this is due to its crystallization to the β-phase, as confirmed by its X-ray diffraction pattern.