Copper sulfide associations from sulfide ores of the recent Logachev hydrothermal field (MAR, 14°45′N) were studied using ore microscopy, X-ray, and microprobe methods. It was first established that sulfides of the Cu-S system in oceanic ores are mostly represented by non-stoichiometric minerals forming fine polymineral mixtures. The latter include djurleite (Cu_1.93S-Cu_1.97S), anilite (∼Cu_1.79S), geerite (Cu_1.54S-Cu_1.64S), spionkopite and yarrowite (Cu_1.13S-Cu_1.18S), and covellite (Cu_0.97S-Cu_1.03S). Chalcocite and digenite mentioned in previous works are recorded as rare relics and digenite-bornite solid solutions, respectively. Segregation forms and distribution peculiarities of copper sulfides are described. Two main copper sulfide associations are distinguished. The stability of mineral associations, as well as temperature and chemical parameters of their formation, are considered. It is assumed that Cu sulfides primarily precipitated from the high-temperature solutions in the form of hexagonal chalcocite and then was successively replaced by hypergene minerals: chalcocite-djurleite-anilite-geerite-spionkopite-yarrowite. The eventual product of this replacement is represented by covellite. The formation of this succession is related to leaching of copper from chalcocite under the influence of cold oxygen-saturated seawater and is considered as representing an initial stage of underwater hypergenesis, which precedes the formation of oxide minerals.