The study presents first Re-Os age data of molybdenite from the region at Babyak Mo-Ag-Au-W-Bi-base metal deposit, in combination with electron microprobe and laser ablation inductively coupled plasma mass spectrometry results for molybdenite aggregates. The Re-Os geochronology of the analyzed samples defines age at 52.6 ± 0.2 to 53 ± 0.2 Ma of the ore-forming process in the Babyak area. It marks a distinct fertile Early Eocene event in the Cretaceous-Paleogene evolution of the Rila-West Rhodopes batholith.