The short range structure in amorphous Ni 2 B has been investigated by high spatial resolution neutron diffraction. Three specimens of the same chemical composition but with different isotopic content of nickel, nat Ni, 60 Ni and φ Ni, were examined. The B-B, B-Ni and Ni-Ni atomic pair correlation and the Bhatia-Thornton density-concentration correlation functions were derived with high accuracy. The first neighbour atomic distances, the width of their distribution and the coordination numbers are given. The existence of first neighbour B-B distance at 0.187 nm is established. The distribution width in the first coordination shell for unlike atoms was found to be significantly smaller than that for similar type atom pairs.