The isothermal section of the Ni-Sn-Zn ternary system at 500°C was investigated by means of x-ray diffraction (XRD), and scanning electron microscopy with energy-dispersive spectrometry (SEM/EDS). A new ternary compound with a composition of Ni 36 Sn 42 Zn 22 (in at.%) was discovered in the present study. The space group of this compound is P43m with lattice parameter a = 0.88283(4) nm. Two ternary phases, i.e., s 1 and s 2 , which are derived from a¢-Ni 3 Sn 2 and b-NiZn, respectively, were observed to be present at 500°C. The solubility of Sn in Ni 2 Zn 11 was determined to be about 3.5 at.%, and that of Zn in Ni 3 Sn to be about 5 at.%.