The objective of this paper is to illustrate the limitations of classical PID controllers in controlling time delay systems with integrating transfer functions. Generally, the control of integrating processes is more difficult than the classical-stable open-loop processes. Especially, integrating processes existing time delay make difficult the control operation. Numerous, PID strategies have been proposed for these systems recently. Therefore, using a polynomial approach, Coefficient Diagram Method (CDM) has been proposed in order to obtain a better performance for these systems. The controller design by CDM is based on the choice of the coefficients of the characteristic polynomial of the closed loop system according to the convenient performance criteria such as equivalent time constant, stability index, and stability limit index. The studies on this method illustrated that the CDM provides a significantly improved performance both for the reference step input tracking and for the disturbance rejection. Also the control system provides the smallest settling time and the most robust performance to the parameter changes. An example are presented for an integrating process with time delay to illustrate the effectiveness of the proposed method and compared it with existing ones. It is shown that CDM design is more stable and robust whilst giving the desired time domain performance.