Since its foundation in 1948, the United Nations (UN) contributes to guaranteeing pace in the world through numerous actives, among which peacekeeping operations (PKO) have always obtained particular relevance. The blue helmets intervene, in the framework of chapter six of the UN Charter, in countries that have recently experienced a conflict, with the aim of starting a process of stabilization. These operations have often encountered difficulties of various kind, as environments not much in favour of an intervention of an international type or the impossibility of efficaciously operating given the resources available. In the worse cases, the security operators have suffered acts of violence, in particular the years between 1992 and 1996 have been among the bloodiest ones, counting about 300 victims among the military personnel of the UN. If the following developments have registered a more positive trend, the data relative to the last four years (2013-2017) reveals a worrisome peak in the number of victims among the blue helmets: about 175. As a consequence, the leadership of the glass building has decided to investigate more deeply into which could be the causes of the recent increase and has charged retired General of the Brazilian Army Carlos Alberto dos Santos Cruz with writing a report for studying the case. The text, published in December 2017, is the result of numerous visits to UN missions in Mali, in the Central African Republic, in Congo, and in South Sudan, where information was collected and interviews were conducted. It is important to note that the operations have not been chosen by chance, but rather they are the ones that have registered the highest number of victims in the last years. The report highlights the gaps present in some peacekeeping missions and suggests recommendations aimed at increasing the security of UN operators.