Most of the process industries are handling Multi-Input-Multi-Output (MIMO) system by using the classical Proportional-Integral-Derivative (PID) controller although there are wide researches in advanced control techniques. However, finding a good value for the controller parameters might be very challenging and best tuning approach need to be considered to obtain a better performance. In this paper, biggest-log modulus (BLT) tuning method is adopted to tune decentralized PID controller based on 2x2 MIMO system and the effectiveness of the tuning method is observed. A comparative study on the settling time, overshoot and integral absolute error (IAE) are evaluated when a step change in u1, u2 and disturbance is introduced to the system. The simulation result demonstrates that BLT method has a better performance for a disturbance change response compared to set point change response. © Published under licence by IOP Publishing Ltd.