This study critically analyzes the activities of the Canadian Council on Social Development during the inter-war years. This investigation is preceded by an examination of nineteenth and early twentieth century Canadian child welfare reform efforts and brings to light the contours of th e Council's organizational growth and development from its formation as the Canadian Council on Child Welfare in 1920, through its organizational transformations to the Canadian Council on Child and Family Welfare in 1932, and to the Canadian Welfare Council in 1935. The study concludes in 1941 with the resignation of the executive director, Charlotte Whitton, after twenty-one years of service with the Council. In the early 1920s the Council, as a quasi-public national organization on child welfare, moved to define and promote principles and standards in child welfare nationally and to coordinate voluntary child welfare developments provincially and locally. Setting the stage for the assumption of the family welfare mandate the Council implemented social surveys as a means of stimulating provincial and local child and family welfare reforms. In this process the organization moved to reform and modernize child welfare legislation, encourage the development of provincial administrative standards, promote local autonomy and the development of community based child and family welfare organizations and services, and moved to solidify a role for voluntary philanthropy and the profession of social work. The advent of the Depression provided the Council with the opportunity to become an authority in the field of relief administration. The social policies which were advanced in the 1930s were informed by a philosophy of "social aid" which rationalized the responsibilities of the voluntary and public sectors. The Council's social welfare policies called for the development of national, provincial, and community planning strategies, the setting of federal and provincial standards of relief administration and conditional grants for the development of provincial social services, contributory social insurances, and relief at need-based systems of public assistance administered by the field of social work. The growth of the Council's eight divisions of service in this period was driven by the provision of research and advisory services to the provinces, community surveys, community organization activities, efforts to promote child and family welfare reforms, the documentation of relief expenditures and conditions, and the transfer of the federal child welfare division. The Council's most important contributions include the promotion of national child welfare standards, the modernization of child protection legislation· and the expansion of children's aid societies across Canada, the growth of the voluntary sector in the child and family welfare field and the social work profession, the development of a blueprint for the organization of public and voluntary sector social welfare services, and the stimulation of social policy planning at community, provincial, and federal levels during the 1930s in response to the exigencies of the Depression.