Direct methanol fuel cell is a promising electrical energy source. Performance improvements, such as higher energy density and improved electrocatalyst are hot topics in fuel cell research. The goal of this study is the introduction of the Positron Emission Tomography (PET) as molecular imaging technique in the visualization of the methanol fuel cell process. The compound specific imaging method, using a small PET camera and radiolabeled 11 C methanol, can visualize the electrocatalytic processes, the coverage degree and the distribution of the methanol and its derivatives on the total electrocatalyst surface. The undesirable methanol crossover effect was also detected by imaging the additional layers of the cell. The fuel cell layers were studied in different conditions, such as well-functioning and temporarily or permanently degraded, during short-and long-term operations. The experimental results confirmed the PET imaging method is applicable in the methanol fuel cell development.