The favourable immediate prognosis that can be offered to the newly diabetic child of today is in contrast to the prognosis in the pre-insulin era. Nonetheless, the fact that vascular complications occur after a relatively few years of the disease point to deficiencies in our understanding of the disease and possibly to errors in our treatment. Current concepts of the etiology of these sequelae and their relation to past control are examined and lead to the conclusion that while vascular disease is probably inherent in the diabetic state, the degree of damage and the consequent loss of function can be modified to some degree at least by maintenance of good control. In this respect the role of serum lipids and the dietary fat content are reviewed but definitive conclusions seem unwarranted. Oral hypoglycemic agents have been shown to have little or no place in the treatment of juvenile diabetics. Continued careful observation of diabetic patients in addition to basic research is needed to improve our understanding and management of this disease.