Samples with a composition ZrNiSn were synthesized by a combination of mechanical alloying (MA) and consolidation by either Spark Plasma Sintering (SPS) or hot pressing (HP). Appropriate stoichiometric ratios of the starting materials were milled under an inert atmosphere in a high energy ball mill for 6 hours, achieving a half-Heusler phase. X-Ray diffraction patterns of as milled powders and consolidated samples were compared and analyzed for phase purity. Thermal conductivity, electrical conductivity and Seebeck coefficient were measured as a function of temperature in the range 300 K to 800 K and compared with measurements reported for high temperature solid state reaction synthesis of this compound. HP samples, compared to SPS samples, demonstrate increased grain growth due to longer heating times. Reduced grain size achieved by MA and SPS causes increased phonon scattering due to the increased number of grain boundaries, which lowers the thermal conductivity without doping the base system with addition phonon scattering centers.