This paper presents a new approach for temperature control of an injection molding machine (IMM) that uses a model predictive control (MPC) strategy. The control system consists of a number of single-input-single-output model predictive controllers, each associated with a particular temperature zone. What distinguishes this approach from others is how the MPC strategy exploits knowledge of temperature interaction between adjacent zones and the effects of back pressure, to develop individual temperature controllers for each zone. This is achieved by decoupling the interaction between zones. The new thermal controller was simulated and implemented with good results on a 150-tonne IMM using a series of comparative experiments. (C) 2004 Society of Plastics Engineers.