An exploratory study was conducted on the implementation of Part H of Public Law 99-457, with emphasis on the involvement of health care providers. A series of 10 focus group discussions were held with health professionals (mostly nurses and physicians) in five states (Colorado, Hawaii, Maryland, North Carolina, Ohio). These health care providers identified the role of service coordinator as the key to a family's successful entry to and maintenance within a family-oriented system of multidisciplinary services. Three models of service coordination varying by the degree of severity of the child's need for services were suggested. These included: (1) the physician as coordinator (usually for more severe impairments); (2) physician as medical coordinator with another professional coordinating services from other agencies and programs (the most prevalent model); and (3) physician as consultant to a multidisciplinary team (for cases where the disability is mild or less medically complex). Recommendations include examination of state directives related to service coordination for severely impaired infants and toddlers, specific allocation of funds for the position of service coordinator, and statewide planning for systems of service coordination. (DB)