Abstract: Level control is very important for the successful operation of most chemical and biochemical industries since it is through the proper control of flows and levels that the desired production rates and inventories can be achieved. The aim of this study was the development and real time implementation of a Wiener Model based PI Controller (WMPIC) for a conical tank level process. The conical tank level process exhibits severe static non-linear behavior and dynamic characteristics. Here, a WMPIC structure was developed by the way of compensating the process static non-linearity. Tuning rules suggested by PadmaSree-Srinivas-Chidambaram (2004) and Ziegler-Nichols (1942) were considered here for designing the controller. The real time implementation results of wiener model based PI controller were compared with those obtained using a conventional Linear PI Controller (LPIC). The performance of these controllers was analyzed in terms of Integral Square Error (ISE) criterion. In addition to this, the robustness of the controllers was also analyzed.