The Kultuminskoe deposit is located within the Gazimur metallogenic zone in eastern Transbaikalia. Mineralization is associated with the Middle–Upper Jurassic Kultuma pluton composed of subalkaline rock series ranging from quartz monzonites and quartz syenites to granites and of monzodiorite dikes. Dikes of Late Jurassic age are composed of subalkaline gabbro. Analysis of fractionation trends of major and trace elements suggests that the monzonitoids prevailed in the Kultuma pluton and the dike complex formed through the differentiation of subalkaline basaltic melt from an enriched mantle source. The formation of the gold–copper–iron–skarn and medium-temperature veinlet-disseminated polysulfide and epithermal Ag–Te–Bi mineralization as well as iron–magnesia and silica–alkaline metasomatites was a long multistage process during the general evolution of the ore-magmatic system.