Auxetic materials are comprehensive materials with a negative Poisson's ratio. They tend to thicken when applied to vertical tensile stresses, as opposed to conventional materials, perpendicular to the applied force. Currently, available results for the deflection of circular isotropic thin plates are valid for a limited positive Poisson's ratio. In this paper, the deflection of isotropic circular thin plates under static loading and clamp boundary conditions is investigated by the semi-empirical method and in addition to positive Poisson's ratio, Negative Poisson's ratio (Auxetic material) is examined. The results show with increasing negative Poisson's ratio, the deflection of thin plate increases. Also, the auxetic plate has about two times more deflection than the conventional plate. Auxetic materials can be used in defense, biomedical and sports industries.