Abstract This paper performs a techno-economic analysis of natural gas-fired combined cycle (NGCC) power plants integrated with CO 2 selective membranes for post-combustion CO 2 capture. The configuration assessed is based on a two-membrane system: a CO 2 capture membrane that separates the CO 2 for final sequestration and a CO 2 recycle membrane that selectively recycles CO 2 to the gas turbine compressor inlet in order to increase the CO 2 concentration in the gas turbine flue gas. Three different membrane technologies with different permeability and selectivity have been investigated. The mass and energy balances are calculated by integrating a power plant model, a membrane model and a CO 2 purification unit model. An economic model is then used to estimate the cost of electricity and of CO 2 avoided. A sensitivity analysis on the main process parameters and economic assumptions is also performed. It was found that a combination of a high permeability membrane with moderate selectivity as a recycle membrane and a very high selectivity membrane with high permeability used for the capture membrane resulted in the lowest CO 2 avoided cost of 75 US$/t CO2 . This plant features a feed pressure of 1.5 bar and a permeate pressure of 0.2 bar for the capture membrane. This result suggests that membrane systems can be competitive for CO 2 capture from NGCC power plants when compared with MEA absorption. However, to achieve significant advantages with respect to benchmark MEA capture, better membrane permeability and lower costs are needed with respect to the state of the art technology. In addition, due to the selective recycle, the gas turbine operates with a working fluid highly enriched with CO 2 . This requires redesigning gas turbine components, which may represent a major challenge for commercial deployment.