This article examines one of the most debated problems in the ancient history of Central Asia – the migration of a farming population to the southern Khorezm oasis in the lower reaches of the Amu Darya and the scholarly interpretation of this process. The study is based on a comparative analysis of three groups of sources: ancient Greek, Roman and Achaemenid written records together with the Avesta; medieval local narratives, above all the works of Abu Rayhan Beruni and al-Muqaddasi, as well as folk legends preserved in the oasis; and the results of archaeological research carried out in the region from the mid-twentieth century to the present day. The analysis shows that in the early sixth century BCE the south-eastern part of the Khorezm oasis underwent a fundamental economic transformation that had no roots in the preceding Amirabad and Kuyusay cultures of the Early Iron Age. Fortified settlements, wheel-made pottery production and irrigated agriculture appeared within a short period, which most researchers explain by the arrival of a population group from the southern agricultural regions. The article systematises the principal hypotheses concerning the original homeland of the Chorasmians (the Merv and Herat regions, the Serakhs oasis on the middle Tejen, the area between Margiana and Bactria) and the causes of their migration (the campaigns of Cyrus II, the taxation policy of Darius I, hydrological changes in the Akes river basin). It is concluded that the archaic culture of southern Khorezm was formed on the basis of the interaction of several cultural traditions brought by migrants and the local pastoral population, and that the two-stage migration model, dating the main wave to the late seventh – sixth centuries BCE, best corresponds to the combined evidence of the written and archaeological sources.