Ag-MFe2O4 (M = Co, Mn) nanocomposites were synthesized and loaded onto carbon supports. As-prepared Ag-MFe2O4/C demonstrated higher catalytic activity for oxygen reduction reaction (ORR) than Ag+MFe2O4/C. The direct coupling and electron transfer between Ag and MFe2O4 in nanocomposites were proposed to enhance their catalytic activities. The Koutecky-Levich plots confirmed a direct four-electron reaction pathway for the ORR on Ag-MFe2O4/C. Furthermore, Ag-MFe2O4/C showed superior catalytic activities and excellent stability for oxygen evolution reaction (OER). Thus, Ag-MFe2O4/C nanoparticle are potential non-Pt candidates with bi-functional catalytic activity for ORR and OER. (c) 2017 The Electrochemical Society. All rights reserved.