The issue of contacts between the ancient Mordvins and the early Slavs has become relevant again after finding a group of early medieval sites in the upper reaches of the Voronezh River that are associated with the Dnieper cultural circle. The paper aims to prove contacts between the ancient Mordvins, who left burial sites with cremations in the middle Tsna region (mid-second half of the 7th century AD), and the population of the Upper Voronezh cultural group of the early Middle Ages. To meet the aims the following tasks were set: to consider the origin of the rite of burning the burial grounds in the middle Tsna region during the mid-second half of the 7th century AD; to determine which of the neighbouring archaeological cultures it shows the greatest similarity with; to analyze the clothing complex of the Middle Tsna burial grounds of the specified period with the view to identify the presence of decorations of the Dnieper cultural circle. The research included a comparative analysis of the body cremation rite of the middle Tsna region burial grounds of phase A stage 1 (according to O.V. Zelentsova) with synchronous antiquities of neighbouring regions. As a result, its similarity to the cremations of the Ryazan-Oka culture was established and the assumption of its Slavic origin was rejected. At the same time, the correlation of jewellery originating from some of the earliest burials at cemeteries in the middle Tsna region with materials from the Dnieper cultural circle made it possible to assume the presence of contacts between the indicated communities and suggest a hypothesis that the Upper Voronezh region could be the territory from which objects of the Dnieper appearance, as well as Byzantine imports, came to the Middle Tsna.