The objective of this work is to develop an optimization methodology to design adaptive truss structures with multiple optimally placed active members. The finite element model of truss structures with piezoelectric members is presented. The performance function is built for optimal design of active members at discrete locations in the output feedback control system by using the method proposed by K. Xu et al. Genetic algorithm (GA) is used to search the optimal locations of active members for vibration suppression of adaptive truss structure. A numerical example of the planar truss structure with two piezoelectric active members is performed, and the corresponding experimental set-up is designed for active vibration control. The experimental results demonstrate the effectiveness of optimal placement of active members for adaptive truss structures using genetic algorithm.