The atomic and electronic structure of YFeO3 surfaces at the formation of oxygen vacancies are investigated by the methods of quantum-mechanical calculations. The (100), (001), and (010) surfaces are considered. The dependence of the formation energy of surface oxygen vacancy on its concentration and type of surface is shown. (100) surface oxygen vacancy has the lowest formation energy. During the formation of vacancies on the surface, the 3d states of Fe split into bulk, surface, and near-surface states.