The control of pH is one of the most difficult challenges in the process industry because of the severe nonlinearities in the behaviour of the system. Different approaches for the pH control are proposed in various literatures. In the present study, control of pH using internal model controller for a neural networkmodel based pHprocess is proposed. Modelling of the pH process is supposed to be a difficult task because one needs to have knowledge about the components and their nature in the process stream in order to model its dynamics. I this work, neural networkmodel is proposed using the first principle equation of the nonlinear pHand used for controlling the pH process effectively using IMC based PI.