A non-destructive inverse method is developed to determine internal temperature distribution of the PEMFCs. In this study, the attention is focused on global measurement for the irregular temperature distribution at the interface between the carbon plate and the membrane electrode assembly (MEA) based on the measured temperature data on the outer surface of the end plate. A direct problem solver capable of predicting temperature distribution in the solid layers of the PEMFC under various conditions is incorporated in the inverse approach to provide temperature solutions. In this report, a concept of point-by-point temperature prediction is presented. This approach is particularly suitable for determining irregular temperature distribution that is difficult to handle by the existing polynomial-function approach [C.H. Cheng, M.H. Chang, Predictions of internal temperature distribution of PEMFC by undestructive inverse method, J. Power Sources, in press]. A number of test cases are considered in this study. Some irregular temperature functions are specified and regarded as exact temperature distributions to predict. Meanwhile, the influence of uncertainty in the measured temperature data on the outer surface is evaluated. (c) 2004 Elsevier B.V. All rights reserved.