Projections in the near term call for 20,000 fuel cell stacks/year and 1 GW/year for proton exchange membrane electrolyzers. To meet these manufacturing quantities as well as to lower costs, quality control methods are needed associated with the high-volume manufacturing of membrane and electrode assemblies (MEAs) used in fuel cells and electrolyzers. Manufacturing variations can include inadequate catalyst loadings, degraded catalysts, nonuniform catalyst and ionomer dispersions, and poor catalyst-membrane adhesion, all of which can lend the MEA to not performing to design specifications. There is presently a lack of rapid, highly accurate, in-line and real-time quality methods to assess the viability of manufactured MEAs before they are incorporated into higher value fuel cell and electrolyzer stacks. This project will develop an in-line quality control measurement system enabling reel-to-reel MEA quality assessments to be made in real-time with inspection rates less than 1 second per MEA. The success of this MEA quality control sensor innovation will help lower the manufacturing costs for producing MEAs for the fuel cell and electrolyzer markets. These lower costs will directly translate into lower cost fuel cells and electrolyzers along with increasing the reliability of fuel cells and electrolyzers.