This work focuses on the design of a simulated moving-bed rector (SMBR) where reaction A -> B + C takes place. The reactive-separation regions were determined for two reactive systems: (1) inversion of sucrose, with enzyme introduced in the unit through the eluent stream and Michaelis-Menten reaction kinetics, and (2) A -> B + C reaction, with immobilized enzyme and linear reaction kinetic law. In both systems the reaction species exhibit linear adsorption isotherms. The steady-state equivalent true moving-bed reactor (TMBR) analogy was applied in the algorithm used for determination of the reactive-separation regions. The influence of the mass-transfer limitation, reaction rate, product purities, reactant Henry constant, and SMBR configuration on the shape and position of reactive-separation regions was analyzed. It was shown that in certain conditions the reactive-separation regions extended out of the separation regions obtained for nonreactive SMB for product (B and C) separation. (c) 2005 American Institute of Chemical Engineers.