The collapse of the cold war system brought detente in the global scale, but at the same time there appeared conflicts of the new type of no less importance for the international security. That is why maintenance of the world peace remaining the priority, inspires the authoress to undertake the study of this issue. The direct motive were the last occurrences concerned with the conflict on the Balkan Peninsula. Both the place and the character of those events, excesses standing for barbarity, bring to mind not distant history of the World War II. In the paper she presents the course of the Balkan conflict, beginning from the diplomatic activities of states, ending in the military operation of NATO, and tries to estimate the activities both strictly European and American ones. The Balkan Peninsula became the experimental range for the new aspirations of EU. It shows the abilities of EU to resolve international conflicts in its own capacity, which gives the large views of the real possibilities and limitations of the concept of creation and realization of the Common Foreign and Security Policy (CFSP). Observation with insight of the conflict gives Poland the priceless information when it comes to the concept of which our state should choose as far as its security and defense are concerned.