Peacekeeping by the United Nations is a unique and dynamic role held by the Department of Peace Operations to provide security and the political and peacebuilding support to countries. The interventions are aimed to reduce hostility between the conflicting parties and also create fruitful grounds for a sustainable peace process in the conflict area. In recent years, it has been observed that the demand for the UN to intervene in active conflicts has increased. Depending on the effectiveness of UN peacekeeping missions in reducing violence on the battlefield, this demand may be warranted. In this data article, an argument is tested claims that the effect of the UN troops size on reducing the battle-related fatalities is stronger once a ceasefire agreement is in place.