A membrane electrode assembly (MEA) is one of the core components of proton exchange membrane fuel cells (PEMFCs). Its structure is sandwich-like, comprising a proton exchange membrane (PEM), electro-catalyst layers and gas diffusion layers (GDLs). The sealing structure and performance of a MEA are the key factors that influence the performance and the security of fuel cells or fuel cell stacks. In this paper, the sealing structures of MEAs of PEMFCs are reviewed and classified as follows for the first time: (1) PEM direct sealing structure; (2) PEM-wrapped frame sealing structure; (3) MEA-wrapped frame sealing structure; (4) Rigid protective frame sealing structure. The compact MEA-wrapped frame sealing structure has a clearly greater advantage over the other structures for its more convenient stack assembly and lower cost. Another promising sealing structure is the rigid protective frame sealing structure. We hope this review can provide references for the sealing arrangements of PEMFCs available to designers. (C) 2013 Elsevier B.V. All rights reserved.