The present work investigates the effect of the FACTS devices on distance relay operation. FACTS devices have different advantages in power system performance, stability, and load ability. In this paper, FACTS technologies' effect on the distance protective relay is presented using the measured impedance between the fault location and the relaying point. Different factors and parameters are changed to see their impacts on the studied system. It is shown that the measured impedance is affected by the presence of the FACTS devices depending on its type (series, parallel, and hybrid), fault location, and the operation point of the FACTS device. The analyses present that the shunt FACTS devices' effect may cause overreach problem to the relay; however, series FACTS devices may cause under reach problems in distance characteristics. MATLAB 2019b does the simulation test; the results of the simulation proved the mathematical analysis. The numerical analysis in this paper may be used for researchers in fault analysis and protection coordinators.