A simulation study has been carried out to assess the performance of DMC (dynamic matrix control) for an ethylene-propylene-diene polymerization reactor. The regulated outputs are ethylene composition, diene composition, and Mooney viscosity of the polymer product. The simulation results show the excellent capability of DMC to control product quality during setpoint changes in product specifications (servo control) and changes in production rate and catalyst activity (regulatory control). DMC is proved to be superior to the conventional control approach and appears to hold a considerable promise for such a reactor system.