The recruitment of children for use in armed conflict is one of the so-called ‘six grave violations’ against children in conflict, as well as one of the most significant consequences of armed conflict in terms of children’s wellbeing. Children in many parts of the world are being recruited by armed groups and forces, assuming both ancillary and combat roles in conflict. Commissioned by Save the Children, PRIO has estimated the number of children who live at risk of being recruited or used in armed conflict during the period 1990–2020. Our estimates suggest that the risk of recruitment has steadily increased over the past 30 years, with the highest recorded number of children at risk in 2020. This policy brief describes the methodology and main descriptive statistics on children at risk of recruitment and use in armed conflict around the world.