Vacuum deposition techniques were used to prepare composition spread samples of thin film Fe-C-N catalysts. After deposition, catalyst films were thermally treated to induce structural and composition changes. Catalytic activity was found to be at its largest when the films were annealed at ca. 800{degree sign}C. At this temperature, partial graphitization of the film occurred but it still contained a significant amount of nitrogen, which is required to have an active site. Above 800{degree sign}C, a significant quantity of Fe3C, which is inactive and not stable in acid, was formed. Single composition thin films were also prepared, thermally treated, and tested in a 50-cm2 fuel cell. After thermal treatment of the catalyst, the fuel cell performance was significantly improved.