Herein, nanostructured ternary Ni-Ti-B alloy synthesized by mechanical alloying from the elemental Ni, Ti, and B powders by high energy ball milling is described. The synthesized alloy of nominal composition of Ni70Ti10B20 results in the formation of a unique stable phase of Ni21Ti2B6, which happens to be stoichiometrically very close to Ni70Ti10B20 in the cubic symmetry. The synthesized alloy samples also show amorphization together with the formation of nanocrystalline phases of Ni21Ti2B6 at both early and later stages of the alloying process. Thermal analysis carried out on Ni70Ti10B20 induces crystallinity and reveals the formation of crystalline Ni-Ti-B ternary alloy, Ni21Ti2B6, above 523 K, confirming the stability of the ternary crystalline phase of the alloy. The magnetic saturation of the alloy is measured as 0.95 emu g(-1) for the starting amorphous phase that increases to 9.05 emu g(-1) for the crystalline phase upon annealing. Correspondingly, the coercivity value for the annealed sample is reduced to 70 Oe from 194 Oe for the amorphous phase. This is the first time that an evidence of the stable crystalline Ni-Ti-B ternary alloy is reported.