A feedback control configuration for composition regulation in a continuous stirred tank reactor ( CSTR) via manipulations of the jacket coolant/heating temperature, was studied. Under the assumptions that composition measurements are delayed and chemical kinetics are uncertain, a linear cascade ( master/slave) control configuration is proposed, which leads to asymptotic regulation of the output composition about a given desired set point. The master control is derived by taking the reactor temperature as a virtual control input leading to low-gain linear PI feedback. The slave controller is derived by addressing a signal tracking problem that results in high-gain linear PI feedback. The final result is a cascade of linear PI feedbacks. The performance of the proposed control configuration is illustrated with numerical simulations of a methyl methacrylate polymerization reactor.