Recently, an opinion has been established about the broad chronology of the medieval cultures in the study of the Middle Ages of the Trans-Urals. Particularly, the period of existence of the Bakal Culture has been considered to fit within the framework of the 4th–13th centuries, and the Yudino Culture within the 6th–13th centuries. Based on the general chronology of the archaeological sites, as well as discovery of materials of different cultures within the same settlements, the researchers suggested a certain level of interaction between representatives of the Bakal and Yudino Cultures. Such ethno-cultural situation probably had to be accompanied by economic, social or military aspects of the interaction of the medieval communities. However, we cannot readily accept the coexistence of representatives of the Bakal and Yudino Cultures, since no multicultural burial complexes have been found and no syncretic has been observed in the material culture. Thus, one of the main objectives was to detail the chronology of the medieval complexes and to identify the chronological phases. To address this problem, we have assessed all known dated archaeological sites of the medieval period, examined by stationary excavations and subjected to absolute and relative dating, 36 sites in total. Using the comparative typological method, an attempt was made to narrow the chronological framework of material complexes for each site. All radiocarbon dates have been calibrated using OxCal 4.3 program and IntCal13 calibration curve with a confidence interval 95,4 %, and 68,3 %. The absolute dates were then correlated with the relative dates. As a result, two chronological periods were defined: 4th–8th and 9th–13th centuries. The first period correlates with the period of existence of the Bakal Culture. The later dates, obtained from the few single-layer sites of the Bakal type, are not supported by the material complexes and the presence of burial grounds of this time. Archaeological sites of the Yudino Culture appeared in the territory of Trans-Urals in the 9th century. This has been reliably confirmed by the appearance of single-layer settlements and monocultural necropolises dating to the developed medieval period. In summary, we conclude that the chronology of the Medieval cultures of the Trans-Urals does not overlap, and the analysis of microstratigraphy of the majority of settlement complexes allows observing the gradual replacement of some cultural groups by others.