This study examines the migratory phenomenon in Greece from the establishment of the State (1833) until today. Two different kinds of migration are discerned: emigration and immigration. The study begins by examining those parameters linked to the emigration phenomenon, such as the tradition of the Greeks involved in the Diaspora, economic crises and problems involved in the slow industrialisation of the country. At the same time, the study delimits such concepts as “refugee” and “emigrant”, terms that are not always clearly distinguished. It sets out the procedure followed concerning the sending of Greek immigrants to a foreign country and the changes initiated with regard to countries of settlement (United States, Europe). It analyses the causes of emigration, provides quantitative data, draws attention to diverse administrative aspects of the migratory policy (monitoring of the country, limitations on the right of emigration, repatriation), and refers to the competent administrative bodies. In addition, the study sketches the developments in political debates concerning the migratory phenomenon (role of the “American Hellenic Educational Progressive Association” (AHEPA), opinions concerning the industrialisation of the country, the participation of immigrants in national elections). With regard to the phenomenon of immigration, two kinds of immigration (ethnic and economic) as well as their respective characteristics are noted. In the case of ethnic immigration, attention is drawn to international and bilateral treaties that regulated the massive arrival of refugees whose origins were Greek. Attention is also drawn to the competent administrative bodies which took charge of the settlement and reparation of refugees. In the case of economic immigration, the massive arrival of immigrants (of foreign and Greek origin) in the country during the 1990s is described, as well as the development of both the modern migratory policy and competent administrative bodies.