In this paper, we consider the linear quadratic optimal control problem for multiparameter singularly perturbed systems in which N lower-level fast subsystems are interconnected through a higher-level slow subsystem. Different from the existing methods, a new method is developed to design a near-optimal controller which does not depend on the unknown small parameters. It is shown that the resulting controller in fact achieves an O(parallel tomuparallel to(2)) approximation to the optimal cost of the original optimal control problem. (C) 2003 Published by Elsevier Ltd.