This paper presents a new algorithm called Firefly Algorithm to solve the well-known power system Economic load dispatch problem. Firefly Algorithm is a novel nature-inspired algorithm inspired by social behavior of fireflies and the phenomenon of bioluminescent communication between them. Our proposed algorithm utilized fireflies food searching mechanism to optimize economic load dispatch problem in power system. This makes the algorithm more convergence and less complexity. It is also appropriate for high-speed real-time application due to fast and less execution time. In order to demonstrate the effectiveness of the proposed algorithm has been tested with the standard 6-bus, IEEE-14 bus and IEEE-30 bus system with several heuristic load patterns. The numerical result reveals that the proposed algorithm can provide appreciably better solutions within reasonable time.