Catalytic membrane reactors are reviewed as applied to opportunities and applications within petroleum refineries. Since so many inorganic membranes take advantage of H-2 permselectivity and H-2 demands are increasing in a refinery, there are a number of interesting process applications being considered. H-2 production can be enhanced by using Pd based membranes for dehydrogenation, oxydehydrogenation, and decomposition reactions. Permselective H-2 membranes could be used for carrying out selective hydrogenations of organic substrates and coupled reactions. These membranes have been also considered for enhancing steam reforming reactions for the production of bulk H-2, the water gas shift reaction, and the conversion of natural gas to syngas and liquid fuels. Dense oxide membranes are also being developed for the selective oxidation of CH4 to syngas. For many of these processes, the formation of carbon during steam reforming or dehydrogenation reactions will always be a huge hurdle towards any successful commercial application of Pd membranes to such processes. In any of these applications one has to understand production problems associated with the metal membranes, the refinery demands for high purity H-2, and the reactor fabrication hurdles; these will be evaluated with recent examples. For all these applications, the critical issues that need to be resolved for the commercial use of catalytic membrane reactors will be discussed.