This chapter deals with an asymptotical stability of the fractional-order unified chaotic systems. A unified system is presented to show that three chaotic dynamics of the Lorenz, the Chen, and the Lü systems are in the same structure. Dynamics of the Lorenz, the Chen, and the Lü are categorized in a unified system with a same structure. This system will be distinguished different when an only relevant parameter a is accordingly tuned. A systematic linear state feedback controller is gained to stabilize these systems. This controller will be shown increasing the stability region with respect to their integer order counterpart. The stability region will be accordingly increased with respect to their integer order alternative. Simulation results are demonstrated for the Chen and the Lü fractional-order systems to illustrate the effectiveness of the proposed control scheme. © Springer Science+Business Media, LLC 2012. All rights reserved.