A two-phase lattice Boltzmann model is employed for direct numerical simulation of liquid water transport in the turning regions of serpentine gas channels in proton exchange membrane (PEM) fuel cells. Two different types of serpentine gas channels with either a smooth U-shaped or a sharp right-angled turning region are examined. Numerical results indicate that a smooth U-shaped turning region is beneficial to liquid water removal in a serpentine gas channel. An increased gas stream velocity or channel surface contact angle can further assist the process. Liquid water tends to accumulate in the sharp right-angled turning region because of the acting direction of the gas shear force. Increased gas stream velocity and surface contact angle are not very helpful for liquid water removal in the right-angled turning region under all the tested conditions. This numerical study is intended to provide improved fundamental understandings of liquid water transport mechanisms in serpentine gas channels of PEM fuel cells. (C) 2012 Elsevier B.V. All rights reserved.