The paper preliminary deals with the definition of the notion of State and of its most important functions, explaining the essential and characterizing aspects (identity, territorial sovereignty and political and economic independence) and also its changing way of being of its political structure as regard as its democraticity. Then the paper underlines the fundamental distinction of human rights between political and civil rights, on the one hand, and social, economic and work rights on the other. The paper underlines the logic fact that the latter are propaedeutic to the former in order to effectively have the civil and political rights protected and implemented. Third part of the paper deals with the actual problem of mass migrations by examining intended and unintended causes and effects and by assessing whether the so-called “migrants” may be qualified as “refugees” according the general and conventional international rules with specific regards to rights and duties of the State towards foreign nationals for the purpose of protecting fundamental rights and freedoms. In the last part the paper examines challenges and threats brought by mass migrations to individual and State security and to peaceful development of international relations among States pursuant to general and conventional international rules. The paper also suggests some solutions to this problem.