The 1989 survey involved interviews with child welfare directors and developmental disabilities/mental retardation directors in 49 States. The survey covered the organization of services, the use of interagency agreements for coordination, cooperative/coordinated service delivery, philosophical differences among providers, and whether the system works for children. The limited empirical data and anecdotal reporting suggest that a substantial number of children with developmental disabilities and their families currently receive services from child welfare agencies, particularly from protective and out-of-home placement services. There is debate over whether the number of such children is increasing. No particular pattern of effective service coordination appears to be emerging. There is an immediate need for research that more accurately identifies the number and types of disabilities experienced by children receiving services in child welfare programs. Federal encouragement and resources are required to improve State interagency planning specific to children with developmental disabilities and their families. 1 table, 7 references.