Catalytic reactions in multiphase systems are prevalent in production of fuels, bulk and specialty chemicals, pharmaceuticals, materials, food and feed, etc. Making useful products, at economical yields and selectivities, from the diverse chemistries in such a broad range of applications requires the ability to quantify the interplay of transport phenomena and kinetics. This is the domain of catalytic reaction engineering. In this paper the current state of the art of this discipline is briefly reviewed with the emphasis on describing the increased use of fundamentals in multiphase reactor modeling and scaleup. Packed beds, trickle beds, slurry bubble columns, simultaneous reaction and separation via catalytic distillation, membrane reactors and trickling solids adsorbent, as well as nonconventional multiphase reactor operations are discussed.