In this work, a new analytical solution for simulated moving bed rector (SMBR) in the presence of mass transfer is presented. A reaction of type A -> B + C, where each species exhibits a linear type of adsorption isotherm, was assumed. The linear driving force model was used to describe the intraparticle mass transfer. The proposed solution is based on the steady-state equivalent true moving bed reactor (TMBR) analogy and allows the calculation of the liquid and solid concentration profiles in the SMBR. The TMBR analytical solution predicts internal concentration profiles and process performances, providing better accuracy, when compared with results of dynamic simulation of real SMBR. The main advantage of the presented solution is the fast determination of the reactive-separation regions in the presence of mass transfer limitations, according to the required product purities and reactant conversion. The analytical solution was used to study the influence of the rate of the reaction, the mass transfer rate, the number of the columns per section, and the reactant adsorption affinity on the reactive separation regions.