A review. This review addresses the catalytic reactions performed in microstructured reactors, which are more and more recognized in recent years as a novel approach for chem. and chem. process industry. They are particularly suited for highly exothermic and fast reactions allowing temp. control and isothermal operation. A brief evaluation of the advantages for gas-phase, liq.-phase, and gas-liq.-solid reactions carried out in miniaturized devices is discussed. Alternative designs to achieve microstructured fluid patterns, besides microfabrication, are also described. [on SciFinder (R)]