Barite mineralization occurs in recrystallized dolomitic limestone of the Devonian Meydan Formation in the Haskoy, Azikli, and Elmabulak districts of Mus region, southeast Anatolia, Turkey. Mineralization presents as veins in fractures and faults in the host rock. Mineral assemblages consist of barite, pyrite, chalcopyrite, sphalerite, galena, chalcocite, covellite, malachite, azurite, haematite, limonite and quartz. Barite concentration ranges from 31 to 55 wt.% in mineralized veins and from 8 to 46 wt.% in host rock. 8 S-34(CDT) values of barites range from 26.3 to 42.10 parts per thousand, suggesting formation by bacterial reduction of Silurian-Devonian seawater (delta S-34 approx 23-24 parts per thousand) sulfate. Sr-87/Sr-86 isotope ratios of barite are between 0.711204 and 0.714088 and host rock ratios are between 0.71186 and 0.712683. O-18 isotope values are range from 12.3 and 14.7 parts per thousand for host rocks and from 14.7 and 19 parts per thousand for barites. The barite mineralization formed as a result of circulation of sea water was heated by granite intrusion along fractures in a continental shelf environment. S-34 enrichment of sea water sulfate by bacterial activity and leaching of Ba and Sr from continental host rocks contributed to the production of the barite mineralization. Post-mineralization metamorphism resulted in barite recrystallization and remobilization as well as the production of other sulfide phases.