We conducted a multi-isotope study of five fifth-century AD cemeteries in modern-day Hungary to determine relationships between nomadic-pastoralist incomers-the historically documented Huns and other nomadic groups-and the sedentary agricultural population of the late Roman province of Pannonia. Contemporary historical sources describe this relationship as adversarial and destructive for the late Roman population, but archaeological evidence indicates high levels of hybridity between different groups. We undertook carbon, nitrogen, strontium and oxygen isotope analyses of bone collagen, dentine and tooth enamel at Keszthely-Fenékpuszta, Hács-Béndekpuszta, Győr-Széchenyi Square, Mözs and Szolnok-Szanda to examine these relationships through past subsistence practices. The patterns at all sites indicate medium to high animal protein consumption with little evidence for a significant contribution of aquatic resources. All populations relied to a great extent on C4 plants, most likely millet. Within each population, diet was heterogeneous, with significant variations in terms of animal protein and C3 and C4 plant consumption. High levels of intra-population and individual variability suggest that populations made use of a range of subsistence strategies, with many individuals exhibiting significant changes over their lifetimes. Rather than being characterised only by violence, the historically-documented influx of nomadic populations appears to have led to widespread changes in subsistence strategies of populations in the Carpathian basin. Nomadic-pastoralist groups may have switched to smaller herds and more farming, and, conversely, local populations may have integrated with a new economic system based on animal herding.