This study describes and analyses the influence of immigration and integration of German expellees and refugees in the former administrative district of Osnabrueck. It is a contribution to a new regional social and economic history as well as to the history of integration of German refugees after World War II. The main goals are to close the gaps in regional pre and post war history of population, administration and economy. To a certain extent this thesis is of global importance with respect to the history of refugee integration in Germany. It deals with the refugee administration that was in place until the 1970s as well as the methodology of econometric analysis. The latter is used to show the process of modernisation from an agrarian economy to one that is dominated by industry and services. The applied methods are those of narrative history as well as social and econometric statistics on historical long-term analysis. The study describes and analyses the regional history of population, administration and economy, the latter with special respect to history of farming. To show the impact of expellees on social and economic structure, each of the three sections is analysed in a similar way: Chronologically by comparing the history and structures from about 1900 to 1945 with the period after World War II up to the 1970s. Geographically by comparing regional to country and national statistical patterns. It can be shown that the refugee administration suffered from early "ad hoc administration" days until its agony in the 1970s from the dualism with the traditional social administration. At the beginning there was no survival without the support of British military government, which consideres this area as a test field for the influence of new democratic conditions on pre-democratic administrative structures and daily work. In the 1950s the influence of military government was replaced by political power of refugee organisations and party. There decline leads to agony and subsequent take-over by traditional administration in the 1970s. The study shows the role and impact of refugees as part of the labor immigration in between the "Fremdarbeiter" and the "Gastarbeiter" on regional economy. It displays the intersectoral changes by the shifts in figures and index’ of gainfully employed people (domestic and refugees) demonstrating the shift towards an industrial or service oriented economy. From a refugee point of view there was no integration in the sense of equal opportunities in the job market as compared to native Osnabrueckians. This led to a decline in social status, especially for those who had been independent farmers in the east. The "integration" by discrimination and declining social status caused geographical and job mobility especially among the younger refugees – into better paid and modern jobs. Qualified refugee labour sped up the long term process of industrialization. Those sub areas which in pre-war times had been dominated by an agricultural sector on a 19th century level changed to an industrialized or service driven level within 15 years – much faster than during the Industrial Revolution. The study shows also that refugees had been a very successful political vehicle for claiming and getting public economic subsidaries – which mostly reached not the immigrants but native (Emsland-) farmers and companies. All in all the integration of refugees was a bivalent process of interdependent mutual adaption: On the one hand that of immigrants towards the conditions to live and work in the Osnabrueck area. On the other side the impact of refugees onto speed and direction of post war development and modernization of regional structures. The general result is that refugee immigration and integration had a major impact on regional post war development and modernisation of an administration with a pre-democratic understanding and an pre-war economy dominated by agriculture.