Abstract A unified method has been proposed to obtain single PID tuning rule for different types of processes with enhanced disturbance rejection. It provides consistently better performance compared to several well-known methods for stable, integrating and unstable processes for the same degree of robustness. Based on the Ms-value τc guideline is provided over a wide range of θ/τ ratios. An analysis has been performed for the uncertainty margin in the different process parameters for the robust controller design. It gives the guidelines of the Ms-value settings for the PI controller design based on the process parameters uncertainty. Furthermore, a guideline has been developed for the uncertainty margin in the different process parameters (k, τ and θ).