An especially noteworthy part of the Firsovo archaeological area is a group of early burials at the fl at-grave cemeteries Novoaltaisk-Razvilka, Firsovo XI, and Firsovo XIV. Nine radiocarbon dates have been generated for those cemeteries at various laboratories: two by the liquid-scintillation (LSC) method and seven using the accelerator mass spectrometry (AMS) method. The dates were calibrated using OxCal version 3.10 software. Dates for the Chalcolithic Bolshoy Mys culture burials at Novoaltaisk-Razvilka and Tuzovskiye Bugry-1 burial 7 match the previously suggested ones (around 3000 BC). Certain Neolithic burials in the Altai differ from others in the position of the bodies (fl exed on the side). They were dated to the late 5th to the early 4th millennia BC by the AMS method. Burials belonging to the “cultural core” of Firsovo XI, then, fall within the Early Neolithic (68 % interval, 5710–5460 BC; 95 % interval, 5740–5360 BC). The date 9106 ± 80 BP (GV-02889), obtained for Firsovo XI burial 18, may be somewhat accurate, pointing to the Final Mesolithic or Early Neolithic. Both the date and the cultural characteristics of this burial (sitting position, abundant ocher) are accompanied by the craniometric distinctness of the male cranium (huge total size).