Fifteen patients began insulin treatment in a diabetic day-care unit and 14 patients began insulin treatment in hospital. The cost per patient of initiating insulin treatment in hospital was nine times the cost in a day-care program. In general, the disease of patients with juvenile-onset diabetes was initially under poorer control in those admitted to hospital than in those in the day-care program. However, the day-care juvenile with disease under poorest control was comparable to the most severely affected patient admitted to hospital. No major differences in the improvements in control achieved by the two programs were found.