In this paper the Control of an UAV is designed by an Image Based Visual Servoing (IBVS). The trajectories are generated by the IBVS to track a target. The dynamic model describing the Quadrotor behaviour is established taking into account all internal and external aerodynamic forces and moments, for simulation. Furthermore, actuators and sensors dynamics are also considered. To overcome all the nonlinearities, as well as the strong coupling in 3D position and Euler angles of Quadrotor system, a robust Sliding Mode Control (SMC) is designed. Unlike several literature works in this topic, the SMC control uses only an approximated model of the Quadrotor. In other words, SMC does not use the dynamic inversion of Quadrotor model. The Quadrotor is endowed a virtual camera to perform visual tracking, in order to evaluate the robustness of our controller.