Abstract: This study presents an alternate algorithm to solve the Optimal Power Flow problem incorporating Flexible AC Transmission System Devices (FACTS) in a multi machine power system using Genetic Algorithm. Using the proposed method, the location, their type and rating of FACTS devices are optimized simultaneously. Among the various FACTS devices, Thyristor Controlled Series Compensator and Unified Power Flow Controller are considered. The proposed algorithm is used for finding the optimal choice and allocation of FACTS devices, such that the overall system cost which comprises of generation cost and investment cost of FACTS devices are minimized.