It was the purpose of this study to determine what the juvenile diabetic knows about his disease. It is evident from the data presented that this knowledge increases with age; however, there appears to be a significant difference between the knowledge of children 6 to 11 years old and that of children 12 years and older. It is advised that self-care not be urged upon diabetics until the time at which they can comprehend the important fundamentals of their disease and its management. The possibility of adverse effects of such early training is briefly discussed.