Water management on proton exchange membrane fuel cells is one of the biggest issues that stop the effective commercialization of this promising technology. Due to water flooding, the performance of fuel cells decays rapidly at high current densities. To better design fuel cell electrodes, a mixed wettability pore-size distribution model was developed, and used to estimate the effective transport properties of dry and partially flooded fuel cell porous layers. Using this model, microporous layers and conventional cathode catalyst layers were studied. Results revealed that mass transport limitations can be significantly improved by controlling the wettability and microstructure of the electrodes.