In this paper, Proportional Integral (PI) Controllers are designed for unstable Multi Input Multi Output system with delay based on the equivalent transfer function (ETF) model. Decoupling method is proposed for multivariable processes. The simplified decoupler is used to eliminate the process interactions between the controlled and manipulated variables. PI controllers are designed for the diagonal elements of ETFs by synthesis method meant for unstable first order plus time delay (FOPTD) systems to give satisfactory performances. Since the unstable system has large overshoot. To reduce the overshoot, a double loop PI controller is designed.