Today, the term security is very complex. The international community, in particular the United Nations, is using its instruments to ensure lasting peace and the stability of international security. The research is extensive and multidimensional and is reflected in the two fundamental chapters of the thesis – Genesis, evolution and contemporary vision of peace support operations, as an element of ensuring national and international security, legal status of peacekeeping operation (PKO) completed with an interesting and very important case study, which was the first NATO intervention, as well as a cornerstone for the development of the NATO concept of peace support operations, also it was researched the route of the Republic of Moldova as a security provider in the Kosovo region.