Participation in military activity abroad in peaceful and other missions evolves out of general decision making process within a military structure. It is done in reference to the political and institutional sphere of state’s activity within domestic and international policy. Th e undertaking is decided upon by the highest administrative body and is made in lieu of state defenses and political interests. As the author points out, decision processes occur simultaneously on three levels: the highest levels of the state administration, the institutional international cooperation arena, and on the level of department of national defense. Th ere are many formal consultations prior to a mission, for example, the consultation between representatives of the state and the office of Th e Secretary General of the UN, on military commitment in peaceful operations. Th ere is unison between this process and the decision making in NATO and EU institutions. Good example of Poland’s commitment in such activity is presented by description in this article of the individual phases of Afghanistan mission. It is based on the mission regulations for the Polish Armed Forces abroad. Particular example focuses on the legal bases for commitment of the Polish Contingent in Afghanistan. Legal aspects are presented with reference to the Polish statutory law documents.