Full Potential Linearised Augmented Plane Wave (FP-LAPW) method was used to investigate the electronic and magnetic properties of NiO doped with Hf and Ta within the frame work of density functional theory (DFT). NiO is found to be stable in rock salt structure. NiO shows conducing characteristics for the lattice constant of 4.155 angstrom. Doping Hf and Ta in the metallic super cell of NiO separately in the doping concentration of 12.5%, the compounds Hf0.125Ni0.875O and Ta0.125Ni0.875O are formed. These compounds of Hf0.125Ni0.875O and Ta0.125Ni0.875O are predicted to exhibit stability in the ferromagnetic phase. The density of states and band structure plots predict that these compounds exhibit half metallic character with formation of energy gap in one of the spins at the Fermi level. The total spin magnetic moments found in these compounds are 12.00689 mu(B) and 10.97628 mu(B).