Thin films of amorphous Co-C-N mixtures which were co-sputtered in vacuum showed good catalyst properties for oxygen reduction in alkaline solution. The optimal catalytic activity was Co0.68C0.16N0.16. The oxygen reduction for these films proceeds via a four-electron pathway and the Co2+/Co3+ redox couple is shown to be responsible for the oxygen reduction reaction. The performance is comparable to transition metal macrocycles in alkaline solutions. Evidently, intact structures of the macrocycles are not necessary for good catalyst activity.