The presence of carbon monoxide in the hydrocarbon reformate fuel is known to have a detrimental effect on proton exchange membrane fuel cell (PEMFC) performance. At Honeywell, we are currently developing two new approaches to remove carbon monoxide (CO) from the reformate prior to its entering of PEMFC stack. These methods are the adsorption/catalytic oxidation of CO (ACO) approach and adsorption/electro-catalytic oxidation of CO (ECO) approach, respectively. Potential advantages of these methods include a higher projected hydrogen utilization efficiency, an increased tolerance to dynamic variation of CO in the reformate output, and relatively simple operation and control. Details of the technical approaches and the experiment results will be discussed.