Summary. The occupation of the steppe region north of the Black Sea by farming or herding groups in the fifth and fourth millennia BC has been a controversial question. At the core of the problem is the changing relationship between Cucuteni-Tripole farming groups in the forest-steppe zone and their neighbours in the true steppe zone. Three phases of this relationship are discussed, in the Early Copper Age, Late Copper Age and Early Bronze Age (c.5000–3000 BC), during which different forms of exchange and acculturation took place, each with its own social and economic characteristics. The role of environmental change, and the significance of burial monuments in the process of cultural convergence, are evaluated. The process is discussed both in terms of general models of social transformation, and by comparison with other areas of Europe where similar processes of interaction were taking place.