The Tertiary extensional setting, the associated magmatism and the thermal and exhumation history of the Eastern Rhodopes provided a positive feedback between several spatially superimposed factors, all enhancing the potential to develop at the Eocene-Oligocene transition a gold-rich hydrothermal system. The geochemical results show, that a single ore fluid from different sources and various precipitation processes might be responsible for the range of ore types (typical low-sulphidation and replacement ores) identified in the studied deposits. Isotopes data reveals intense fluid-rock interactions, which likely mask the original identity of the fluids. The typical element association (Au, As, Sb and Ag) might be caused by leaching metals from sedimentary rocks during extensive fluid circulation through large sedimentary basins. The ore and alteration assemblages reflect the temperature-pressure-time evolution of mineralizing fluids and suggest that sulphidation with subsequent cooling was a general depositional process in all the deposits. At some prospects the decompression of hydrothermal system allowed local concentration and deposition in high ore grades.