In this study, a damage identification method based on observing the changes in frequency response functions (FRFs) of a structure, due to damage, with taking advantage of differential evolution algorithm (DEA) as an optimization solver is presented. Firstly, by using the FRFs of a healthy structure, damaged structure and analytical model of the structure, an efficient objective function is defined for the optimization. Then, the DEA is employed to solve the optimization-based damage detection problem for finding the location and severity of the damage. The performance of the proposed method is evaluated for a beam and two planar frames by making a parametric study. The numerical results indicate that the method can provide a reliable tool to accurately identify the structural damage.