This paper presents a detailed chronological study of the previously undisturbed burial ground of Choburak-I of the Bulan-Koby Culture in the Northern Altai using a program of comprehensive dating, including AMS 14C dating of human and animal remains (26 14C dates from 12 kurgans in total), and archaeological dating of the associated artifacts. This completely excavated cemetery contained numerous grave goods and various organic remains (anthropological and archaeozoological) critical for understanding the social and chronological dynamics of this culture during the Rouran period in Altai (second half of the 4th–first half of the 6th century CE). The results of archaeological dating, supported by the largest set of AMS 14C dates for the Bulan-Koby Culture, and further aided by Bayesian analysis, demonstrate the likely continuous existence of the necropolis within the period of 310–400 cal CE, which broadly corresponds to the beginning of the Rouran period in the history of Altai, with a maximum duration of 66 years. The presented results make it possible to consider the necropolis of Choburak-I as a chronologically defining monument of the Rouran period of Northern Altai and permit a new level of relative and absolute chronological reconstructions for archaeological sites of this region and adjacent territories at the turn of late antiquity and the early Middle Ages.