Lanthanum zirconate La2Zr2O7 is of considerable practical interest as a material for hightemperature ceramic thermal barrier coatings, catalysts, and high-temperature superconductors. The conventional method for La2Zr2O7 solid-state synthesis is based on multiple calcination of zirconia and lanthana powder mixtures at 1500 °C, with intermediate grinding to facilitate the solid-state reaction. This method may not meet the necessary ceramic technology requirements due to the inhomogeneity of the final product, large grain size and poor sintering behavior. To overcome these drawbacks, La2Zr2O7 has been synthesized by coprecipitation-calcination [1,2] and other soft chemistry methods. In this work, we have synthesized nanocrystalline La2Zr2O7 by new solution-free method using mechanical activation (MA) of the salt mixture (ZrO(NO3)2·6H2O + La2(CO3)3·8H2O) following by thermal treatment. MA has been carried out in a planetary mill AGO-2 in air for 30 min at a centrifugal factor of 20 g. The processes occurring during thermal treatment of the mechanically activated salt mixture have been studied using differential scanning calorimetry (DSC), thermogravimetric analysis coupled with mass spectrometry, X-ray diffraction (XRD) and FT-IR spectroscopy. It has been shown that in the course of intensive mechanical treatment in planetary mill alongside with intimate mixing of the reagents and their amorphization exchange reaction occurs, producing lanthanum nitrate and basic zirconium carbonate. The DSC curve of the mechanically activated salt mixture shows a strong exothermic peak at 877°C which is not associated with weight loss and can be attributed to La2Zr2O7 crystallization in agreement with XRD data. Nanocrystalline lanthanum zirconate synthesized by annealing of the mechanically activated salt mixture has been characterized using XRD and transmission electron microscopy. The thermal analysis was performed at the Centre for Thermogravimetric and Calorimetric Research of the Research Park of St. Petersburg State University.