This work presents electronic and thermoelectric properties of ZnO and SrTiO3 in the presence of nitrogen impurity have been investigated by means of the theoretical first-principles calculations. It is found that N-doped ZnO has a smaller band gap compared to the pure counterpart. This material also exhibits the enhanced thermoelectric properties of the positive Seebeck coefficient and higher electrical conductivity per relaxation time. Furthermore, SrTiO3 with nitrogen impurity possess the smaller energy gaps. For thermoelectric properties, ZT of undoped SrTiO3 decreases as temperature increases. Nevertheless, ZT of N-doped SrTiO3 increases with temperature. Therefore, the introduction of nitrogen impurity to ZnO and SrTiO3 is an alternative way to improve their thermoelectric efficiencies. (C) 2018 Elsevier B.V. All rights reserved.