A combined experimental and analytical investigation of single proton exchange membrane (PEM) fuel cells, during cold start, has been conducted. The temperature influence on the performance of a single PEM fuel cell and the cold start failure of the PEM fuel cell was evaluated experimentally to determine the failure mechanisms and performance. The voltage, current, and power characteristics were investigated as a function of the load, the hydrogen fuel flow rate, and the cell temperature. The characteristics of cold start for a single PEM fuel cell were analyzed, and the various failure mechanisms were explored and characterized. In an effort to better understand the operational behavior and failure modes, a numerical simulation was also developed. The results of this analysis were then compared with the previously obtained experimental results and confirmed the accuracy of the failure mechanisms identified.