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Precious metal epithermal sedimentary rock hosted prospects constitute a new class of ore deposits recently described in the Tertiary Eastern Rhodopes of southeastern Bulgaria. The Stremtsi prospect investigated in this contribution is located in a distal location with respect to the main cluster of sedimentary rock hosted Ada Tepe and Rosino gold prospects of the Eastern Rhodopes. The Stremtsi prospect is hosted by a Priabonian clastic sedimentary rock sequence overlying metamorphic rocks of the Central Rhodopean dome. The eastern part of the Stremtsi prospect contains high gold grades and is characterized by a strongly silicified zone including adularia and silicified dolomite blades diagnostic for boiling conditions during ore formation in such low sulphidation epithermal systems. The western part of the Stremtsi prospect consists of a barite sphalerite and galena mineralization associated with silicification and illite and carbonate alteration. Both parts are underlain by subvertical quartz carbonate pyrite veins. Primary and secondary fluid inclusions respectively in dolomite and barite yield homogenization temperatures ranging between 90 and 247 8C. The salinity of primary inclusions in dolomite falls between 1.9 and 5.1 wt NaCl equivalent whereas the one of secondary fluid inclusions in barite ranges between 0.0 and 3.1 wt NaCl equivalent. The variable homogenization temperatures reflect post entrapment re equilibration of the fluid inclusions whereas the salinities were preserved and the inclusions in dolomite are interpreted in terms of dilution of a saline fluid in the western part of the Stremtsi prospect. The sulphur isotope compositions of sulphides from Stremtsi range mainly between 24 and +4‰. They are not diagnostic and can be attributed to magmatic metamorphic and sedimentary sources. They overlap with the main compositional range of sulphides from other sedimentary rock hosted epithermal systems and reveal the existence of hydrothermal fluids with common characteristics during ore formation throughout the Eastern Rhodopes. In addition at Stremtsi negative d34S values between 242.6‰ and 28.8‰ combined with framboidal pyrite and elevated d34S values of +7.0‰ to +19.5‰ support locally derived sulphur generated respectively by bacterial and thermochemical sulphate reduction. Modelling of O C and Sr isotope data of dolomite support the above described ore forming processes. A positive correlation between d18O (+12.7‰ to+19.7‰ V SMOW) and d13C (22.8‰ to +1.5‰ V PDB) values for dolomite from the eastern silicified and gold enriched zone of the Stremtsi prospect is satisfactorily modelled by boiling between 140 and 180 8C of a deeply circulating fluid characterized by d18O and d13C values of +5.5‰ V SMOW and 21.5‰ V PDB respectively and radiogenic strontium leached from the metamorphic basement rocks or its clastic counterparts in the Priabonian host rocks. By contrast negative correlations of d18O values (+13.4‰ to +23.3‰ V SMOW) with d13C values (20.6‰ to 23.9‰ V PDB) and 87Sr/86Sr ratios of dolomite from the western barite and base metal rich zone are adequately modelled by a shallow low temperature (70 8C) intra formational fluid recharged by meteoric water which interacted with organic matter that is coal layers and carbonate rocks from the Priabonian host sequence mixing with a deep moderate temperature (190 8C) 87Sr enriched fluid characterized by d18O and d13C values of +5.5‰ V SMOW and 21.5‰ V PDB respectively. Disequilibrium conditions revealed by sulphur isotope thermometry of two galena barite pairs yielding discrepant temperatures of 190 and 306 8C are consistent with fluid mixing. A plateau age of 37.57+0.31 Ma obtained by 40Ar/39Ar dating of adularia from Stremtsi is interpreted as a maximum age because of the saddle shaped age spectrum. Combined with 40Ar/39Ar age data from previous studies it reveals that the sedimentary rock hosted epithermal prospects constitute an independent regional and older ore forming hydrothermal system distinct from the younger volcanic rock hosted epithermal deposits of the Bulgarian and Greek Eastern Rhodopes.