We report on the direct growth of novel Pd-Cd nanostructures with controllable composition via a facile hydrothermal reduction method. Our study demonstrates that the addition of Cd significantly changes the morphology and properties of the formed Pd-Cd nanostructures. Our electrochemical measurements show that the Pd-Cd nanostructures with 10-15% of Cd possess the highest capacity for hydrogen sorption, over 15 times greater than the nanoporous Pd networks. The significant enhancement by Cd can be attributed to a combination of the formation of small dendritic structures, dilation of the lattice constant, and decrease of the crystallite size. The easy fabrication and high capacity for hydrogen sorption make the novel Pd-Cd nanomaterials very promising for hydrogen storage.