One of the central problems in control theory relates to the design of controllers for stabilization of systems. The paper deals with the problem of computing all stabilizing values of the parameters of Lag/ Lead controllers for linear time-invariant plant stabilization. It is well known that linear controllers of Lag/ Lead type are still widely used in many industrial applications. In this paper, an extension of a new approach to feedback stabilization based on the Hermite-Biehler theorem to the Lag/Lead controller structure is given. In addition, the problem of stabilization of uncertain systems defined by an interval plant is studied using the Kharitonov and the Hermite-Biehler theorems. The proposed method is analytical and it can be applied successfully using today's advanced computer technology. Examples are included to illustrate the method presented. (C) 2003 Elsevier Ltd. All rights reserved.