n this study, the ternary catalyst, PdPtAu, was synthesized for the electrochemical formic acid oxidation reaction. The catalyst was prepared through the co-precipitation using NaBH4 as a reducing agent. The status of catalyst formation and the extent of average particle size were known by X-ray diffraction (XRD) and transmission electron microscopy (TEM). For this work, we accomplished electrochemical analyses for the PdPtAu, Pd, Pt, and Au, which defines each activity for formic acid oxidation. In durability tests, half cell and single cell tests show even better stability than the Pd and Au catalysts. Stripping tests were carried out after durability tests. Based on results, the ternary PdPtAu catalyst is less deactivated than the Pd, while the catalyst shows higher activity than the Pt. The PdPtAu catalyst represents high resistance for poisoning as compared to the Pd. We demonstrate the stability of the PdPtAu catalyst in the 3-electrode electrochemical system and single cell tests. After 2 h-operation, the deactivation degree of PdPtAu shows 27% loss of the initial current density, while Pd and Pt catalysts lost 39% and 57% of them, respectively.