In this paper, the placement of piezoelectric sensors and actuators has been studied. Genetic algorithms have been used to find efficient locations of piezoelectric sensors and actuators of a smart composite place. Locations of both sensors and actuators have been determined with consideration of controllability, observability and spillover prevention. The composite specimen with piezoelectric sensors and actuators has been prepared according to the optimization result. The experimental vibration control shows significant vibration reduction for the controlled modes with little effect on the residual modes. In addition, the closed loop system is observed to be robust with respect to system parameter variations.