The authors address the ratio of archaeological cultures and ethnic groups of the Roman time in the Aestii settlement zone in the South-Eastern Baltic, with the help of archeological sources and written accounts. Comparison of archaeological data with written accounts does not allow us to come to an unambiguous conclusion that, at some period, the Aestii left the territory of East Prussia and their territory was occupied by other peoples, for example Germanic ones. The ethnonym of Aestii is applicable primarily to the bearers of the Sambian-Natangian culture, but it can also cover other cultural groups of the coastal population, primarily in the zone of the Wielbark culture. The Sambian-Natangian culture, as well as the Wielbark culture, are heterogeneous in origin. In both cases there is a Germanic cultural component, but it is not the only one. In the Sambian-Natangian culture of the Roman period, the German influence is expressed in the funerary rite and in material culture, while its appearance is associated not only with the Wielbark influence, but also with the Scandinavian impulses. To what extent the rather homogeneous cultural appearance of the bearers of the Sambian-Natangian culture reflects their ‘ethnic’ unity is a question beyond the competence of archeology alone.