Archaeological materials recovered from excavations of settlements and cemeteries of prehistoric cultures in the Middle Danube basin offer new evidence for the production of metals by the beginning of the Eneolithic (late neolithic) period. The identification of malachite, azurite and galena indicates that these minerals were extracted from the upland ore-bearing zones and transported to the lowland, alluvial river valleys for processing and smelting at settlement sites. For the first time metallurgical slags, found in association with malachite ores, crucibles, and copper/bronze artifacts, suggest that copper was smelted as early as the fifth millennium BC. Detailed analyses of these slags have identified a unique find of a tin-bearing copper slag, raising the question of bronze production during the fifth millennium BC.