The problem of controlling (possibly open-loop unstable) continuous free-radical solution polymer reactors with temperature, level and flow measurements is addressed. The application of a nonlinear constructive control procedure, with emphasis on the attainment of linearity, decentralization, robustness and model independency features, yields: (i) a measurement-driven control scheme with PI volume and cascade temperature loops, a ratio-type feedforward free monomer controller, and a material balance molecular weight (MW) controller, and (ii) a closed-loop nonlocal stability criterion coupled with conventional-like tuning guidelines. The methodological developments connect the nonlinear geometric and constructive control design techniques with conventional-like schemes employed in industrial polymer reactor control. The proposed approach is illustrated and tested with a representative example through simulations. (C) 2006 Elsevier Ltd. All rights reserved.