The application of membrane gas separation to CO2 capture from a coal gasification process is one potential solution to reduce greenhouse gas emissions. This review considers the potential for either H2- or CO2-selective membranes in an integrated gasification combined cycle (IGCC) process. In particular, the advantages and disadvantages of metallic, porous inorganic and polymeric membranes are considered. This analysis is extended to consider membrane technology as an enhancement to the water-gas shift reaction, to drive the production of hydrogen above the thermodynamic limit. The review concludes with a brief overview of the economics of incorporating membrane gas separation into the IGCC process and gives an indication of the potential economic use of membrane gas separation technology in the IGCC process.