Osmium isotope composition in the studied sulphides from the Ashadze hydrothermal field varies in a wide range of values (187)Os/(188)Os from 0.2261 to 1.9709 and is higher than the known isotope estimations for the similar modern oceanic fields. Isotope composition of the host peridotites and gabbro-norites - 0.1234-0.2325 and 0.3062- 0.5664, and can be compared with the data for the Logatchev and Rainbow hydrothermal fields, also developed over ultramafic basement. There is no correlation between the types of hydrothermal sulphides and osmium composition, which evidences to a more complicated character of hydrothermal process than ordinary mixing of fluid with oceanic water.