Self-consistent calculations of the electronic structure of zirconium dihydride are performed in the cubic and the tetragonal phases by the linear muffin-tin orbital method in the atomic sphere approximation (LMTO-ASA). The band structure of non-stoichiometric ZrH1.75 is calculated as well. The effect of the tetragonal distortion and the hydrogen vacancies on the electronic structure and the phase transition in the group IV-metal dihydrides is discussed. It is shown that a satisfactory agreement with the experimental photoelectron spectra is achieved.