This paper presents the Load Frequency Control (LFC) of an interconnected two-area multiple-unit hydro-hydro system. As an interconnected power system is subjected to load disturbances with changing frequency in the vicinity of the inter-area oscillation mode, system frequency may be severely disturbed and oscillating. To compensate for such load disturbances and stabilize the area frequency oscillations,a two area Hydro-Hydro system is considered to be equipped with proportional plus integral (PI) controllers.The effectiveness of proposed frequency controllers are guaranteed by analyzing the transient performance of the system with varying load patterns, different system parameters and in the event of temporary/permanent tie-line outage. The Gains of the PI controller tuned by the Artificial Bee Colony (ABC) Algorithm and The performance of the ABC Controller of the power system compared to that PI controller to establish the optimization superiority. © Research India Publications.