Hydrogen induced modifications to the structural, electronic and bonding properties of HfNi are investigated by performing first principles calculations. The full-potential linearized augmented plane waves (FP-LAPW) code based on the density functional theory (DFT) was used. The charge transfer and bonding between the constituent atoms is examined by means of the Bader's atoms in molecule (AIM) theory. The calculated enthalpies of formation of HfNi, HfNiH and HfNiH(3) are -53.5 kJ/mol atom, -17.3 kJ/molH and -34.6 kJ/molH. They are found to be in a good agreement with the experimental and semi-empirical values. The calculated stability of the hydrides is in agreement with their hydrogen absorption ability. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.