This paper focuses on the load frequency control of two area interconnected reheat thermal systemwith fuzzy-PID controller optimized by gravitational search algorithm(GSA). The gains of the fuzzy-PID controllers are optimized by providing a step load perturbation(SLP) of 1% to area 1in consideration of integral time absolute error(ITAE) as the objective function. The dynamic performances of the system are being analyzed with GSA and PSO optimized fuzzy-PID controllers. The supremacy of the proposed method is depicted in terms of settling time, peak overshoots and undershoots in comparison with a recently published results. Further the robustness of the system is proved by changing the system loading.