Abstract: In this study, a new method has been proposed to determine optimal location and best setting of FACTS controllers. Thyristor Controlled Series Compensator (TCSC) and static synchronous compensator (STATCOM) have been used for improving power system security. TCSC and STATCOM are employed for alleviation of congestion and enhancing voltage stability, respectively. Seeking the best place is performed using the sensitivity analysis. Then optimum rating of TCSC and best sizing of STATCOM is optimized using the genetic algorithm. The effect of TCSC on the network can be modeled as a controllable reactance inserted in the related transmission line. The average model can account for the high-frequency effects and power electronic losses and more accurately predict the active and reactive power outputs of the STATCOM. This paper employs the DIgSILENT simulator and the DPL as a programming tool of the DIgSILENT to show the validity of the proposed method. The effectiveness of suggested approach has been tested on IEEE 14-bus system.