In an interconnected multi-area power system, as a power load demand varies randomly, which results in the variation of frequency, thus leading to load frequency control problem (LFC). The main goals of Load Frequency Control (LFC) are, to hold the frequency and the desired power output in the interconnected power system at the scheduled values and to control the change in the tie-line power flow between control areas. This research involves the load frequency control is done by PI and PID controller, which is a conventional controller. In order to overcome drawbacks, a new Genetic Algorithm-based controller is presented to quench the deviations in the frequency and the tie-line power due to different load disturbances. The proposed controller guarantees the stability of the overall closed-loop system. Simulation results for a real three-area power system prove the effectiveness of the proposed LFC and show its superiority over a classical PID controller and a PI controller.