A reverse microemulsion procedure has been adopted for the preparation of 20 wt % RuxSey/C (where x = 1 and y = 0- 1). This system has been examined for electrochemical oxygen reduction activity. The measured oxygen reduction activity was comparable with that of commercial Pt/C (E-TEK). The activity is due to stabilization of Ru active sites by Se against blocking as a result of (hydr)oxide formation. © 2007 American Chemical Society.