Electrochemical impedance spectroscopy (EIS) technique is well established in recent years to study and diagnose proton exchange membrane fuel cells (PEMFC). In this paper, the recent published research results in this field are reviewed. The EIS technique and equivalent circuit concept are introduced and recent applications of EIS in PEM fuel cell modeling and diagnosis are thoroughly reviewed. The paper also includes outstanding improvements conducted in EIS measurement and hardware. Finally the critical points that can be misinterpreted in the EIS measurement models in the field of PEM fuel cells are discussed. (C) 2013 Elsevier B.V. All rights reserved.