Abstract: A sliding mode control(SMC) method was derived and applied to a rigid body attitude tracking system in the presence of dynamic uncertainties which included uncertainties and variations in its inertia parameters, uncertainties in its control actuator alignment and external disturbances. A feedback linearization was used to obtain the required angular acceleration according to eigen-rotation. The SMC algorithm was derived to make the angular acceleration of the rigid body track the required angular acceleration. Simulation results show that the proposed SMC law is globally stabilizing and insensitive to uncertainties and variations in its inertia parameters, uncertainties in its control actuator alignment and external disturbances.