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In this paper, an improved Artificial Bee Colony (ABC) while called Interactive Artificial Bee Colony (IABC) algorithm is proposed to find the feasible optimal solution of the Economic Load Dispatch (ELD) problem with considering operational constraints of the generators. The aim of ELD problem is to optimum schedule of the online generators generation in the power system for minimizing the total cost of supplying power and satisfying power balance equations subject to operational constraints of the generators such as prohibited operating zones, ramp rate limits, valve-point loading effects, unit generating output limits and multi-fuel options. A generating unit may have prohibited operating zones between the minimum and maximum power outputs due to physical limitations of the power generators. The IABC algorithm describes the food foraging behavior, memorizing and information sharing characteristics of honey bee swarm to find the best possible solution within a reasonable computation time. Effectiveness of the proposed method is demonstrated for three different systems, including 6, 13 and 40 unit generating in comparison with the performance of the other recently optimization algorithms reported in the literature in terms of the solution quality and computation efficiency. The results analysis confirms that the proposed approach has an excellent capability to determine optimal solution of the ELD problems over the other existing methods and enhances efficiently the solutions quality of the power systems.