In the graduate thesis, which covers five major chapters, the natural and forced movement of the population and the causes and types of migration are described. It’s linked to the demographic picture of the European Union countries with the focus on Croatia, and explores the history of migration, its causes and the European Union countries views of the efforts to attempt to resolve the demographic and migration crisis. Migration as well as climate changes have become a global problem of the world and Europe. The ever-greater gap between the underdeveloped and developed part of the globalized world and Europe has come to the payment as it is already visible in the United States. Large migrations, which are both the present and the future of wealthy Europe, are a kind of the reality in rise and the necessity, because by some projections, by 2050, eight billion people will exist, while in developed countries there will be only about one billion. Connecting low birth rates, bad birth politics, economic and population imbalances, and various democratic relations necessarily leads to the need of migration. They are both positive and negative. The country's fresh workforce needs are positive when the required workers come but it is negative if they are not assimilated quickly enough, if they don’t learn the language, and become the useful workforce. Medium-sized developed countries have a big problem with emigration of the fertile and working-age population because it creates a negative migration for the country. The European Union has no unique standpoint in resolving the migration crisis. German and French leading politicians loudly advocate open borders and immigration reception while the countries of the Visegrad group: Hungary, the Czech Republic, Slovakia and Poland strongly oppose such a migrant policy. Other EU members as well as Croatia still have no strong migration policy, but all members agree on the need to preserve the Schengen border.