Hospitalization and use of outpatient health care services during a 1-year period by 369 pediatric patients with cystic fibrosis, cerebral palsy, myelodysplasia, or multiple physical handicaps and 456 randomly selected children without congenital conditions from the Cleveland area were examined. Use of hospitalization and outpatient services by the average chronically ill or disabled child was 10 times that of the average comparison child. Physician specialists, occupational and physical therapists, and school nurses were the major outpatient categories used disproportionately by children with chronic illnesses or disabilities. The major share of health care used by children with chronic conditions was attributable to a small subset of children; All hospital care was accounted for by one third of the children, and three quarters of all outpatient care was accounted for by one quarter of that sample. Hospital care was used at similar rates by the four diagnostic groups. However, amount and type of outpatient care varied by diagnosis, level of functional impairment, race, and income. Estimated average expenditure for health services used by the chronically ill or disabled sample was 10 times that of the comparison sample. Relative distribution of estimated expenditures across types of services differed for the two samples as well as among diagnostic categories.