Pure forms of Zirconium diboride (ZrB2) nanocrystals could successfully be synthesized by mechanochemical method. Synthesis of ZrB2 nanocrystals from Zirconium route was tried for the first time. The importance of zirconium sources is a cardinal factor to obtain the purity of the crystalline forms of ZrB2. All past methods involved ZrO2 source for the synthesis which always entrained the traces of ZrO2 due to the incomplete reduction. The present study also revealed the factors like ball to powder weight ratios on the final product properties. In this study synthesis of ZrB2 nanocrystals were compared using both Zr and ZrO2 routes. Products were characterized by XRD, scanning electron microscopy, transmission electron microscopy, BET method, and specific density analysis. The synthesis using Zr produced slightly larger nanocrystallites compared the sizes obtained via ZrO2 route. Surface areas of the products were found 32-88m(2)/g depending upon the milling parameters used.