A simple and effective method is presented in this paper to account for the mutual coupling effect on the nulling of antenna arrays. Deep and precise nulls can be achieved using the method with mutual coupling effect considered. Formulas for two-element and three-element arrays are derived from a general model. Simulation and experimental results of two- and three-element microstrip patch antenna arrays are provided to demonstrate the effectiveness of the formulation in the nulling of antenna arrays including mutual coupling effect.