The current investigation deals with the weight minimization of truss structures accomplishing the simultaneous shape, size, and topology optimization. In this regard, this study presents an effective algorithm called integrated particle swarm optimizer (iPSO) as an optimization tool. The iPSO combines favorable features of the standard PSO with an efficient concept of 'weighted particle' to improve its performance. In addition, 'improved fly-back' technique is introduced to handle the problem constraints. The proposed methodology is tested on a series of benchmark problems and the obtained results are compared with those available in the technical literature. The iPSO achieves the results which are capable of competitive with those obtained by other techniques used for simultaneous optimization of truss structures and reported in the literature. Furthermore, the relative simplicity of the formulation can be considered as one of the significant features of this method.