Recent excavations of Neolithic sites in the middle Euphrates have uncovered samples of obsidian. These have been analysed in conjunction with obsidian from Anatolian sources. There is evidence for the diversification of the sources of supply with the addition of eastern Anatolia to the Cappadocia region during the early PPNB. This diversification increased in the early Halaf period. The presence of obsidian from Nemrut Dag in the middle Euphrates is indicated for the first time in the early PPNB.