Membrane reactors have attracted considerable attention in recent years, due also to the recent extensive investigations into microporous ceramic membranes, since in such systems reaction and separation are performed simultaneously. Moreover, conversions greater than traditional equilibrium may be obtained, while in a conventional plug-flow reactor conversions are limited by thermodynamic constrains. When the membrane integrated in this new kind of reaction system is highly selective for the product of interest, its recovery directly during the reaction is possible, avoiding or reducing the separation units downstream the reactor. It is also possible to perform two or more reactions in the same device: the membrane could be selectively permeated by a product of the first reaction, and then this product becomes the reactant of the second reaction. In this paper, recent applications of these systems are presented and discussed.