Lithium metazirconate Li2ZrO3 with a monoclinic lattice is synthesized; the lattice parameters are: a = 0.5432 nm, b = 0.5427 nm, c = 0.903 nm, γ = 112.72°, and Z = 4. The conductivity of both the stoichiometric compound and samples rich or deficient in Li2O near this composition is determined. The conductivity of the synthesized compound reaches 0.029 S cm–1 at 600°C. The activation energy for the high-temperature segment is 13.8 kJ mol–1. An abnormal behavior (abrupt jump) of the temperature dependence of the conductivity at 430°C is discovered and attributed to a phase transition. The change in the structure in this temperature domain (400 to 500°C) is corroborated by the high-temperature X-ray analysis.