The effects of additives and precipitants on the syntheses of doped LaCrO₃ (lanthanum chromites) were studied by hydrothermal reaction at temperature ranges of 100℃ to 230℃. LaCrO₃ nanopowders were synthesized by hydrothermal methods using several types of precipitants such as NaOH, KOH, NH₄OH, and NH₂CONH₂. The influence of Sr, Ca and Co doping on the lanthanum chromites prepared by hydrothermal method were investigated. The synthesized nanopowders were characterized by means of XRD, SEM and densitometer. The electrical conductivity of the doped LaCrO₃ was studied at 750℃ in air by a DC four point probe method. The particles size of undoped LaCrO₃ nanopowder was approximately 100 nm when using KOH as a precipitant. The relative density of lanthanum chromite doped with calcium and cobalt is over 97%. The highest electrical conductivity of La_0.62Ca_0.38Co_0.18Cr_0.82O₃ was 32.75 S/cm at 750℃ in air, which is 30 times higher than undoped LaCrO₃. The density and electrical conductivity are increased by doping cobalt and calcium on the LaCrO₃.