Theoretical models developed describe hollow-fiber memebrane reactors (modules), in which membrane functions as an efficient reactant distributor and the chemical reaction takes place either in the hollow-fiber lumen or in the shell side. Effects of various design and operating parameters, and physical properties on the performance of the reactors were studied. Simulation results indicated that the axial dispersion has to be considered when the chemical reaction takes place in the shell side. It, however, may be neglected when Pe > 40. Theoretical results further revealed that the mass-transfer direction of the reactant through the membrane might be reversed when the chemical reaction in the liquid is extremely fast. Experimental data in the literature obtained from water-treatment processes agreed satisfactorily with the theoretical solutions. Based on the developed solution method, the reaction kinetic parameters can also be obtained conveniently.