Fractional-order systems, which involve integration and derivation of non-integer order, are increasingly being used in the fields of control systems. In this paper based on an extension of the well-known state-dependent Riccati equation (SDRE) techniques, a new method is proposed to design state feedback controllers in a wide class of nonlinear fractional-order (NFO) systems. In comparison with other recent methods, the design procedure of the proposed method is much simpler. The conditions for stability of the equilibrium point of the closed-loop system are investigated and some numerical simulations are provided to show the design procedure and the flexibility of the proposed controller.