In this paper, multi-modal vibration control of smart composite plates has been studied. Piezoelectric films and ceramics have been used as sensors and actuators in surface bonded forms. For modeling and analysis or smart composite plates, an efficient finite element method based on the layerwise plate theory has been used. The effect of thickness changes due to bonded piezoelectric materials and variable in-plane displacement fields on the dynamic, actuating and sensing characteristics have been considered in the finite element formulation. This study includes an optimization method based on genetic algorithms to select appropriate locations of piezoelectric sensors and actuators of a smart composite plate for maximization of control performance. The cost function used in the optimization is based on degrees of controllability, observability, and spillover prevention, Experimental multi-modal vibration control has been also performed. A smart composite plate is prepared according to the optimization results for the experimental works. Coupled positive position feedback algorithms have been implemented in digital signal processing (DSP) system. The control results show that vibration level of the controlled modes has been significantly reduced with negligible effect on the residual modes.