In the study, we discussed the multifactorial determinants of integration processes in the EU and the enlargement of the European community to the new state. In this context, pointed out the problems of international security, European security and the security of the European Union. Discusses the determinants of integration processes and provide security, i.e. terrorism, demographic, legal policy, legislation, alliance, NATO, transatlantic cooperation, collaboration and continental impact of macroeconomic factors. We studied two cases: Latvia and Greece, which was considered the most representative for the present study. The study was conducted in a comparative other countries belonging to the European Union.