Recent research at Areta in the northern side of Chalki Island (Dodecanese) has revealed an enormous quantity of lithics of the Mesolithic period. It is the first time that such an old settlement is located in the area of the Dodecanese, thus extending to the southeast of the Aegean the already known Mesolithic network of sites and creating a sea route from Cyclades to Dodecanese. Apart from the Melian obsidian, there is great abundance of obsidian from Yali of Nissiros used for making tools despite its poor quality. The last few years’ surveys of the Aegean University discovered an extensive Mesolithic site at the southern part of Naxos that follows the usual model of Mesolithic occupation with the selection of sites very close to the sea. The types of tools in both sites exhibit a number of analogies with the sites of the Aegean Mesolithic such as Maroulas in Kythnos and Kerame 1 in Ikaria. Dissimilarities between the above-mentioned inventories result first of all from the fact that different raw materials were exploited. Despite of the missing absolute dates, the regularity and increase of geometrical tools, and the presence of other microlithic forms may suggest that the lithic industry of both sites represents a later phase of the Aegean Mesolithic. The lithic industry of the Upper Mesolithic resembles with the lithic repertory of the aceramic level X of Knossos showing an origin from the Aegean and not from the East.