A new nondestructive damage evaluation method is introduced. The method is able to detect, locate, and size structural damage in a plate-like structure using measured modal parameters of a structure. The solution procedure consists of two steps: First, the method requires constructing a set of flexural damage index equations that represent a rigorous mechanical relationship between damage and curvature of modal flexibility. Second, a pseudo-inverse solution to the resulting system of the over-determined equation nondestructively evaluates damage in a plate-like structure. This study confirms that there is a strong linear relationship between the curvature of flexibility of a structure and flexural damage. In consequence, the proposed method introduces a way to avoid the singularity problem and mode selection problem of the mode shape curvature method and damage index method.