Chaos synchronization is a phenomenon that occurs when a chaotic system drives another chaotic system. If a certain chaotic system is called the master system and another chaotic system is called the slave system, then anti-synchronization is said to occur when the state vectors of the master and slave systems have the same amplitude but opposite signs. This paper derives an important result for the anti-synchronization of identical chaotic systems using sliding mode control. This main result has been established using Lyapunov stability theory. In robust control systems, the sliding mode control (SMC) is often preferred in view of its inherent advantages such as easy realization, fast response, good transient performance and also insensitivity to parameter uncertainties and external disturbances. As an application of this general result, this paper solves the anti-synchronization problem for identical Wang-Chen chaotic systems (2012) via sliding mode control. Numerical simulations using MATLAB have been presented in detail to validate the sliding controller design for achieving anti-synchronization of identical Wang-Chen chaotic systems.