Noble metals such as platinum (Pt) are widely used as catalysts in fuel cells and other heterogeneous catalytic processes. However, there is an urgent need to develop substitutes for pure Pt catalysts to reduce the overall use of precious Pt and at the same time to enhance poisoning resistance. A promising strategy is to design Pt based bi- or trimetallic nanostructures because their unique structures and compositions would enhance their catalytic performance. In this study, we report the synthesis, characterization, and electrochemical evaluation of cubic intermetallic PtCu3 nanocages. The influential effects of several important experimental parameters on the final products have been explored through systematic studies on the growth of PtCu3 nanocages. Relative to the current commercial Pt electrocatalyst, these PtCu3 nanocages possess a more accessible surface area and a unique hollow structure, which contribute to improved electrocatalytic activity in the methanol oxidation reaction.