Transition control is defined in this work as a type of control method that is employed when the plant transitions from one steady state to another as a result of a set point change. Recent approaches have relied on multiple models and centralized or decentralized controller designs to address this issue. This work introduces and develops a transition control framework that consists of multiple fixed and adaptive models within a state-shared non-minimal realization and an H-infinity controller design. The efficacy of this transition control framework is demonstrated on two nonlinear single-input single-output reactors in the face of modeling errors, parameter uncertainties and disturbances. (C) 2003 Elsevier Ltd. All rights reserved.