The professionalization of attention to the needs of children, which has taken place during the course of the twentieth century in areas such as health, education, law and social assistance, underwent an important conceptual development in the first decades of the twentieth century. In the field of social assistance, the structuring of the area of social services marked the introduction of a new variable in formulating policies and practices towards children. This article examines how the subject of social services was discussed, in the context of the American continent, at the Pan American Child Congresses which took place between 1928 and 1948, when its development was proposed as a new tool for social policies, especially for those directed towards children.