This report describes a patient having insulin-dependent diabetes mllitus, with onset at the age of 7 years, who gave birth to three healthy babies without the related development of any diabetic complications as a result of planned parenthood and efforts to normalize her blood sugar. The patient was a 31-year-old American (Caucasian) housewife (of Japanese nationality). When she was 7 years old, she was diagnosed as having diabetes mellitus. Since then, she was treated with NPH insulin, at a dose of 20 U daily. She came to Japan at the age of 19, and married a Japanese man at 20 years of age. When she was 24 years old, she visited our department prior to planning a pregnancy. Because of unsatisfactory blood sugar control she was managed with twice daily (morning and evening) injections of mixed insulin. Blood sugar control became satisfactory, there was no problem of diabetic complication, and she conceived. The patient gave birth to a 2, 140 g baby by induced labor at 38 weeks of pregnancy at 26 years of age. The male baby showed no abnormalities except for low birth weight. She subsequently gave birth to a 3, 224 g male baby by induced labor at 38 weeks of pregnancy at 27 years of age, and to a 3, 305 g male baby by spontaneous delivery at 37 weeks of pregnancy at 31 years of age. The second and third babies showed no abnormalities except for neonatal hypoglycemia and hyperbilirubinemia. The mother showed no complications except for diabetic retinopathy (Scott Ia). This patient is a valuable example of juvenile onset diabetes achieving 3 successful pregnancies as a result of careful family planning. She is the youngest onset diabetic reported in Japan who has been able to achieve a successful pregnancy.