In this paper, we have designed a multiloop proportional-integral-derivative (PID) controller for a nonlinear plant CSTR system. CSTR exhibits extremely non- linear behaviors and habitually have broad operating ranges. The tuning of controller for each operating points of CSTR (continuous stirred tank reactor) is based on internal model control (IMC) tuning method. The main objective of this paper is to design a multiloop PID controller for the control of variable specifically concentration and temperature of multivariable nonlinear system CSTR. A multiple input multiple output (MIMO) process that merges the output of several linear PID controllers, each describing process dynamics at a precise level of operation. The global output is an interruption of the individual multiloop PID controller outputs weighted based on the current value of the deliberated process variable. A common approach to crack the nonlinear control problem such as CSTR is using gain scheduling with linear multiple PID controllers. © Springer India 2016.