Structural and electrical properties of amorphous TiAl films with 50 at.% Ti and 50 at% Al deposited with a compound target by dc magnetron sputtering were characterized by X-ray diffraction (XRD), atomic force microscopy, scanning electron microscopy, and electrical measurements. We found that as-deposited Ti0.5Al0.5 films with a thickness below 1000 nm were amorphous, whereas small hexagonal crystallites could be detected in thicker films. Such layers exhibited a compressive stress which increased with decreasing the thickness of TiAl. The behaviour of stress with the temperature was qualitatively similar in films independently on their thickness. Thermal annealing at 300 degrees C reduced the initial compressive stress and no changes of the phase of TiAl were observed. We correlated these observations with annihilation of point-like defects created by the deposition in thin Ti0.5Al0.5 films or with appearance of nanocrystallites in the amorphous matrix of TiA1. These effects were also responsible for the changes of the resistivity observed at elevated temperatures. We showed that a heat treatment induced by an electronic current with a density of about 2 MA/cm(2) led to the crystallization of TiAl films independent on their thickness. A similar effect could be achieved by annealing the samples at 520-550 degrees C in air or N atmosphere. A significant drop of the resistivity down to 90 mu Omega cm was detected in the annealed films at room temperature. XRD confirmed that two different phases of TiAl (gamma and alpha(2) ) with randomly oriented crystallites appeared in the annealed films.