A novel expert auto-tuner for multivariable control applications is proposed. The main idea of autotuning control methodology is to apply the SISO (Single-Input-Single Output) PID controllers is the MIMO (Multi-Input-multi-Output) environment with appropriate tuning based on the pattern recognition technique. An expert tuning processor is designed to supervise the PID controller to provide good tuning parameters from the observed MIMO response. Customized SISO process identification technique based on pattern recognized is developed for closed loop application. Multivariable tuning is then activated using a detuning factor on the SISO settings.