Patients with insulin-treated diabetes need to be actively involved in their own treatment. We have found that measurement of blood rather than urinary glucose by our diabetic patients leads to greater understanding and enthusiasm as well as to better control of blood glucose. Home blood glucose monitoring is complementary to rather than a substitute for measurement of hemoglobin A1. The latter provides an objective index of long-term control that is of more use to the doctor than to the patient. The former gives the patient information that enables him to master his own disease from day to day.