Findings are presented from a project which aimed to estimate the prevalence of developmental disabilities among Navajo children, aged 0-5 years, living in the Navajo Nation; determine what services they and their families require; and recommend policy and practice to assure that needed services are received. Section I provides a description of the project's background and purpose. Section II analyzes and compares prevalence rates based on diagnostic and functional criteria. A prevalence rate ranging from less than 1 percent to about 2.3 percent (100-644 children) is estimated. Services required by children with developmental disabilities and their families are outlined in Section III, and the present status of services, based on an agency survey, is reported. Policy and practice recommendations focus on four areas: underlying values, guiding policy, direct services, and administrative supports. Among recommendations are the desirability of delivering services in the most appropriate setting, coordinating existing resources, promoting community awareness, strengthening the family support system, developing an improved client information system, and developing a Navajo protection and advocacy system. References are included. Appendices describe provisions of the Early Childhood Education Act (Public Law 99-457) and legislation pertaining to the Navajo Trust Fund. (JW)