Abstract The dynamic structure factors, S(Q,E), for Ni42Nb58 metallic glass have been measured using neutron inelastic scattering on the IN4 spectrometer (ILL, Grenoble, France), over a range of momentum transfer, 0.7<ℏQ/Å−1<8, and energy transfer, 2<E/meV<50. Three samples with the same chemical composition and different Ni isotope content were investigated. The constant-E and constant-Q cuts through the S(Q,E) functions have been obtained. They reveal the E-and Q-dependencies due to the existence of the collective vibrational excitations in Ni42Nb58 glass. At the same time the difference of Ni and Nb atoms dynamics was observed by isotope contrast in the scattered spectra.