The objective of this study is to propose guidelines for the operating temperature range of High-Temperature Proton Exchange Membrane Fuel Cell (HT-PEMFC) considering the overall performance, CO tolerance and durability. To study the effect of temperature on HT-PEMFC performance, polarization curves of the cell operating on respective hydrogen and hydrogen/CO mixture were measured at 5 different temperatures. The electrochemical impedance spectroscopy (EIS) was used to characterize the internal resistances and the results provided the electrochemical analyses and explanations of the temperature effect on the HT-PEMFC. In addition, the stability tests (100 h) were also conducted, which were useful for trade-off study between performance requirement and lifespan of the cell. Results showed that the temperature effect on the cell performance and CO tolerance were less obvious in high temperature range (above 180 degrees C) compared to the low temperature range (below 160 degrees C). However, the degradation of cell performance is faster in the high temperature range. Analysis of experimental results revealed that the optimal operating temperature window is between 160 and 180 degrees C by compromising among the cell performance, CO tolerance and durability, and where the low temperature end of the range is preferred depending on the feeding fuel. (C) 2015 Elsevier Ltd. All rights reserved.