During the last fifty years the city of Benghazi in Libya has attracted huge streams of migrants from villages and small towns. This is due to the pull factors of jobs and social services in the city and to the push factors associated with the neglect of villages and small towns. This resulted in the city quickly increasing in size, leading to rapid population growth, culminating in many economic, social and demographic problems. However, little is known about Libyan migration especially in relation to the challenges posed by internal migration. Therefore, there is a need to examine the phenomena of internal migration and its effect on Benghazi, in order to provide planners and policy makers with up-to-date and relevant information to help them make appropriate decisions. The key aim of this study was to determine and critically evaluate the impact of internal migration on Benghazi using an interpretive approach. This was achieved by combining quantitative and qualitative methods. The empirical core of this thesis is based on field work data, including questionnaire interviews with 150 heads of household who had migrated to Benghazi; supplemented by 10 in-depth narrative studies with selected families; and semi structured interviews with key informants (policy makers) to investigate Government policy and the economic, social and demographic impact of internal migration on the city of Benghazi. The starting point of the theoretical basis of this study is based on theories developed by Ravenstein, Lee and Sjaastad. The research shows that there has been a high rate of migration flow to Benghazi over the last fifty years, and that the economic elements (job opportunities, higher incomes and more regular work) are the most important motives for migrating, in addition to social factors namely attending education and having access to health services. The research found that migration to Benghazi involved a bulk exodus of the whole family unit to take advantage of a better lifestyle in Benghazi. The thesis further reveals that these family streams of migrants have affected the social, economic and demographic situation of Benghazi. Despite the Libyan Government seeking to reduce streams of internal migrants, some of these policies have worked, others have not. There is thus difference between what was planned and what has actually been achieved on the ground, demonstrating the need for research such as this.