Abstract The kinetics of the oxygen reduction reaction (ORR) greatly influences the performance and the costs of electrodes in fuel cells. Commercial platinum based electrocatalysts exhibit the highest performance, but also increase the cost of the fuel cells. On the other hand, carbon based platinum catalyst support is subject to oxidation, which causes agglomeration of the Pt nanoparticles and decrease in performance of the fuel cells. In order to overcome these issues, we have developed and prepared novel catalyst support based on cobalt and molybdenum carbides. Synthesis of CoMoC was done by chemical method, followed by the high temperature treatment. Since the high temperature preparation of the carbides usually produces low surface area materials, we have developed and prepared a specific carbon based matrix, where Co and Mo based precursors were added. High temperature treatment was done at several temperatures, from 750°C to 1200°C. Structural and morphological characterizations were done using XDR, SEM/EDX and BET analysis, and the obtained results show the formation of the mesoporous non-stoichiometric CoMoC, having the highest value of surface area of 97 m 2 g. It was shown that the increase in the preparation temperature leads to increase in the mixed carbide stoichiometry, which was ascribed to the high temperatures needed to transform molybdenum oxide into stable carbide. This catalyst support was used to deposit platinum nanoparticles via boron hydride reduction method to obtain several electrocatalyst having 1-10% Pt on the catalyst support. The electrochemical measurements with the prepared CoMoC and different Pt/CoMoC were done using cyclic voltammetry and linear sweep voltammetry on the RDE in alkaline solution. The stability of the prepared catalyst support and catalysts was evaluated using accelerated test procedure by cycling the potential between 0.65 and 1.0 V in oxygen rich alkaline solution. The ORR kinetics parameters were determined and we found comparable performance of the 10% Pt/CoMoC with the commercial Pt/C (40%), which was ascribed to the non-stoichiometric nature of the catalyst support.