This thesis examines the Irish Army’s service with United Nations forces (ONUC) in the Republic of the Congo, in the period 1960–64, and also studies the political motivation of the Irish Government in acceding to the request from the Secretary General of the United Nations Organisation when, in July 1960, he sought an Irish military contingent to join UN forces in the Congo. The thesis opens by outlining the political situation in the newly established Republic of Congo, touches upon the international relations climate of the cold-war era, and includes an examination of the efforts of the USA, USSR & Belgium to destabilize the new Republic of the Congo. The thesis then studies the political motivation of the Irish Government in acceding to the UN request for a troop contribution to ONUC against the background of Ireland’s foreign policy, spanning the period from the League of Nations to Ireland’s membership of the United Nations Organisation. This thesis then progresses to examine and discuss the readiness condition of the Irish Army in 1960 and also the Army’s response to the UN request for dispatch of troops to the Congo. The military aspects of the Irish Army’s service in the Congo and is then studied, in depth, encompassing the entire four years of Congo service in both peacekeeping and peace-enforcement. In its concluding elements, this thesis evaluates the effectiveness of the Irish Army’s contribution to the UN operation in the Congo. In addition, these concluding elements discuss the challenges presented to military command overseas and includes some less than favourable facets of the Army’s service in the Congo.