-In this paper, a decentralized robust approach is proposed for load-frequency control (LFC) design in a deregulated environment using bilateral market scheme. First, the effect of bilateral contracts as a set of new input signals is taken into account in the control area dynamical model, and then the LFC problem will be formulated as a multi-objective problem to cover robust performance, practical constraint on control action and minimize the effects of load disturbance under wide range of demand changes. A mixed H2/H ∞ is used to solve the problem and design the desired robust controllers. A three control areas power system example with possible contract scenarios and load changes is given to illustrate the proposed approach. The resulting controllers are shown to minimize the effect of disturbances and maintain the robust performance.