In this study, we report Ni-Pd bimetallic nanoparticle catalysts (nanocatalyst) (Ni(1-x)Pd(x)) synthesized by alloying Ni and Pd with varying Pd contents, which exhibit appreciably high H(2) selectivity (> 80% at x = 0.40) from the decomposition of hydrous hydrazine at mild reaction condition with Ni(0.60)Pd(0.40) nanocatalyst, whereas the corresponding monometallic counterparts are either inactive (Pd nanoparticles) or poorly active (Ni nanoparticles exhibit 33% H(2) selectivity). In addition to powder X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) analysis and electron microscopy (TEM/SEM), the structural and electronic characteristics of Ni-Pd nanocatalysts were investigated and established using extended X-ray absorption fine structure (EXAFS) analysis. Unlike the high activity of Ni-Pd nanocatalysts, Pd-M (M = Fe, Co and Cu) bimetallic nanocatalysts exhibit poor catalytic activity. These results imply that alloy composition of Ni-Pd nanocatalysts is critical, where the co-existence of both the metals on the catalyst active surface and the formation of inter-metallic Ni-Pd bond results in high catalytic performance for the decomposition of hydrous hydrazine to hydrogen. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.