Abstract-The paper presents an application of Genetic Algorithm (GA) to solve Economic Load Dispatch (ELD) problems with smooth and non-smooth fuel cost objective functions. Main objective of ELD is to determine the most economic generating dispatch required to satisfy the predicted load demands including line losses over a certain period of time while relaxing various equality and inequality constraints. The unit Min/Max operational constraints, effects of valve-point loading ripples and line losses are considered for the practical applications. Several cases were tested and verified, among of them, two cases of 6-units and 40-units systems including losses with smooth and non-smooth cost functions were tested, verified and compared with previous reported researches. Finally, it can be concluded that GA proves an excellent viability to optimize and solve problems of ELD. Numerical simulations indicate an improvement in total fuel cost savings.Index Terms-Economic load dispatch problem, Genetic Algorithm (GA), Smooth and non-smooth cost functions.