This thesis examines artefacts, raw materials and lithic technology between c. 9200–6200 cal BC in Eastern Central Sweden. The overall purpose of this study is to investigate when people first came to Eastern Central Sweden and where they came from. More precisely, it provides a typological, geo­graphical and chronological survey of artefacts and the use of different raw materials. The study deals with assemblages with artefacts from more than thirty archaeologically excavated sites and loose finds in Eastern Central Sweden. The objects consist of chubby pecked axes, core axes, flake axes, shaft hole picks, microliths and micro burins, points, burins, rulers, uni­facial blade core, conical cores, micro blade cores, blades, drills, re­touched blades and micro blades. The artefacts have been compared with established typologies and chronologies for the rest of the Nordic countries and to some extent Russia and the Baltic States. An analysis of different raw mater­ials present at Early and Middle Mesolithic sites in Eastern Central Sweden was also carried out. The materials are put into a chronological and geo­graphical context. The raw materials included in the study are the non-local rocks flint and Cambrian flint, as well as local raw materials such as quartz, greenstone, local vulcanite, mylonite and red porphyry. From 9200 cal BC there is evidence of the first groups of people in the area, just shortly after that the Weichselian ice cap had withdrawn. Throughout the period studied the artefacts as well as the non-local raw materials exhibit great similarities to those found in the western part of Sweden. The study also shows, regar­ding the use of different raw materials and presence of certain artefacts, that some major events took place, suggesting a new chronological time frame for the Early- and Middle Mesolithic periods. In addition, a discussion re­gar­­ding mobility and migration in Eastern Central Sweden during Early Post Glacial time is carried out.