Carbonate vein mineralization of the ore-bearing rocks of the Vorontsovskoe gold deposit (Northern Urals) represented by calcite and dolomite is considered in the article. Carbonate breccia is one of the major gold collectors on the deposit. Ore-bearing rocks of the Vorontsovskoe deposit (carbonate breccias, volcano-sedimentary rocks) are altered by hydrothermal processes. The lightening of C and O isotopic composition is observed in vein carbonates of ore-bearing rocks of the deposit. Isochron derived age of calcites is 429.8 ± 2.9 Ma, initial 87Sr/86Sr 0.7073537 ± 0000071, MSWD 0.60. The obtained δ13C, δ18O, Rb-Sr and Sm-Nd isotopic data of carbonates of the ore-bearing rocks of the Vorontsovskoe gold deposit indicates mostly crustal nature of mineralizing fluid. Metamorphogenic calcite may inherit the carbonate Rb-Sr isotope system of more ancient sediments trapped in the cement of the ore-bearing breccias of the Devonian limestones. However, the isotopic values of vein carbonates of the altered volcanic rocks may be affected by a magmatic fluid during mineralization.