This research deals with the obsidian-tempered ceramics of the Chalcolithic period in the Southern Caucasus. Samples of obsidian-tempered ceramics from the sites of Aratashen (Armenia) and Mentesh Tepe (Azerbaijan) were analyzed by means of Laser Ablation High Resolution Inductively-Coupled Plasma Mass Spectrometry. These analyses have shown that obsidianswhich came from different sources were used as a ceramic temper for kitchen ware. The Aratashen site in the Ararat Plain, and Mentesh Tepe in the Kura River valley, are localized in very different ecosystems, and at a variable distance from the obsidian sources of the region.Our aim is to compare the strategies of acquisition and use of obsidians at both sites as they are revealed by ceramic temperand lithics. This will allow a discussion of the organization of craftsmanship during the Chalcolithic in two fields of expertise, tool-making and ceramic production.