This paper reports findings of a retrospective longitudinal reconstruction of child welfare service activities in Canada. The first section discusses demographic developments and the child welfare services. It is reported that the increase in the number of children in care in the 20-year period from 1940 to 1960 was to some extent a reflection of the general growth in the child population, and that while developments after 1959 continued earlier growth trends in the welfare services, the number of births declined. Subsequent sections of the paper discuss residential care, foster care and adoption services. The following trends in these services are noted: residential care has increased; foster homes took most children entering care during the 1960's and early 1970's; the average age of children in care has tended to rise; adoptions by stepparents and relatives have become numerically most important. The final section discusses prevention and protection services. It is reported that children receiving protection services appear to come from larger families. Parental failure, neglect, desertion, illness and inability to provide treatment, education and training are said to be the main factors leading to the need for preventive and protective services. Traditional child welfare services are described as an after the fact, rescue service. Preventive services, as presently provided, are said to involve risks for children. It is suggested that policies and programs which address the immediate issue of family breakdown are needed. (Author/RH)