Fuel cells are recognized as having many advantages as power sources, since the theoretical efficiency for conversion of chemical energy to electricity is much higher that that of conventional sources. However their widespread application has been hampered by cost and stability problems. The discovery of new electrocatalysts, especially those that do not involve expensive materials like platinum, is vital for the widespread application of polymer electrolyte membrane fuel cells. Scanning electrochemical microscopy (SECM) is especially useful for doing combinatorial searches of electrocatalysts, since arrays of catalysts can be examined. Moreover, the theory of SECM is well developed, so that one can utilize the current-distance (approach) curves above a substrate to obtain quantitative information about the kinetics of surface processes. I will discuss the basic concepts of fuel cells and SECM, and then recent results on electrocatalysts for oxygen reduction involving simple guidelines based on thermodynamic principles for finding candidate materials and rapid methods of synthesizing and screening these by SECM.