Abstract The phase relationship of the Ni–Pb–Sb ternary system at 500 K has been studied mainly by means of X-ray powder diffraction, differential thermal analysis and metallography. The 500 K isothermal section consists of five three-phase regions, eleven two-phase regions and seven single-phase regions. The maximum solid solubility of Sb in Ni is about 6.25 at.% Sb. The maximum solid solubility of Sb in Pb is about 3.9 at.% Sb. The homogeneity range of NiSb extends from about 49.0 to 52.3 at.% Sb at 500 K. No ternary compounds were found.