A numerical procedure is presented to detect and quantify damages in laminated composite beam and plate-like structures using unified particle swarm optimization (UPSO) technique. The presence of damage in any structure alters its integrity and performance (causes reduction in stiffness and strength) and thus changes the vibration response parameters such as frequency, mode shapes, damping ratio, and frequency response functions (FRFs). These changes in structural response parameters can be used for the identification of flaws in composite structures with the help of an optimization technique. For the present study, natural frequency is used as the diagnostic parameter and UPSO has been used as the optimization technique. An in-house Matlab code has been developed using finite element analysis (FEA) and has been used to extract the vibration responses of undamaged and damaged composite structures. Since composite materials are anisotropic in nature, effect of anisotropic damage on vibration characteristics of damaged composite structures is also presented. It is observed that the anisotropic damage exhibits strong orthogonality and in general, the occurrence of damage changes the vibration characteristics of the structure. It is also observed that as the damage intensity and damage area increase, there is considerable reduction occurring in the natural frequencies. The efficacy of the proposed methodology to identify damages is demonstrated using some numerically simulated composite beam and plate structures with single and multiple damages.