This paper presents the synthesis and analysis of optimal tuning of proportional integral derivative (PID) parameters for different process systems: first order plus time delay (FOPTD), second order plus time delay (SOPTD) and second order plus time delay with lead (SOPTDLD). This work involved optimization of the PID control parameters to achieve the minimization of the integral absolute error (IAE). A set of new and generalized tuning correlations relating the controller parameters to the process parameters was obtained for step changes in set point and load separately. Simulation results showed that the use of the proposed tuning correlations results in superior closed loop performance compared to other tuning techniques previously proposed in the literature. (C) 2007 Elsevier B.V. All rights reserved.