This contribution describes the nationwide implementation of an intensive treatment and education program for type 1 diabetic patients in the clinical routine of the German health care system. Based on the formation of a working group (Arbeitsgemeinschaft Strukturierte Diabetestherapie [ASD]) of presently 57 general internal medicine departments, mainly from secondary and tertiary care levels in city and country hospitals throughout the country, a peer-review quality circle was formed as an official working group of the German Diabetes Association. The participating institutions performed a structured program of intensive treatment and education in all type 1 diabetic patients referred to them on a routine basis. The program includes multiple daily insulin injections or continuous subcutaneous insulin infusion, several times daily blood glucose self-monitoring and self-adaptation of insulin dosages and other aspects of treatment by the patients, and a far-reaching liberalization of the nutrition regimen. The group has attempted to document and to improve the quality of the structure and process of type 1 diabetes care in its participating institutions by a system of peer supervision. Furthermore, all member institutions volunteered to collect outcome data based on systematic 1-1.3 years' follow-up examinations of consecutive type 1 diabetic patients. For the 1997 evaluation of 1,103 type 1 diabetic patients, significant decreases of GHb levels and of incidence rates of severe hypoglycemia (from 0.35 to 0.16 cases per patient-year) and ketoacidosis (from 0.08 to 0.02 cases per patient-year) are presented. The ASD quality circle represents a model to improve principal aspects of type 1 diabetes care on a nationwide basis.