Mineralogical and geochemical characteristics of Cu-Zn sulfide ores from the Logachev-2 and Rainbow fields in the Mid-Atlantic Ridge (MAR) are compared. Both fields are related to serpentinite protrusions. It was established that Zn(Fe)- and Cu,Fe(Zn)-sulfides were deposited in black smoker pipes virtually contemporaneously from pulsating nonequilibrium H₂S-depleted solutions of varying temperature. According to lead isotope data, the deep oceanic crust was a source of lead. The ore from the Rainbow field contains 20 times more Co than the basalt-related ore and shows a high Co/Ni ratio of 46. The ore from the Rainbow field is enriched in ³⁴S (δ³⁴S = 10‰) owing to the permanent flow of cold seawater into the shallow zone of the hydrothermal system. The ore from the Logachev-2 field is enriched in gold by a factor of 8 relative to other MAR localities. The sulfide ores from the Rainbow and Logachev-2 fields have no analogs among MAR ore occurrences as regards their enrichment in Zn, Cd, Co, and Au.