OBJECTIVE: To investigate the basal insulin requirement in total daily insulin dose in Japanese type 1 diabetic patients who use the insulin pump.RESEARCH DESIGN AND METHODS: The basal insulin requirement in 35 type 1 diabetic patients without detectable C-peptide using the insulin pump (Paradigm 712) was investigated during 2–3 weeks of hospitalization. The patients were served diabetic diets of 25–30 kcal/kg ideal body weight. Each meal omission was done to confirm stable blood glucose levels within 30 mg/dL variance until the next meal. Target blood glucose level was set at 100 mg/dL before each meal and 150 mg/dL at 2 h after each meal.RESULTS: Total daily insulin dose was 31.6 ± 8.5 units, and total basal insulin requirement was 8.7 ± 2.9 units, which was 27.7 ± 6.9% of the total daily dose.CONCLUSIONS: Basal insulin requirement is ∼30% of the total daily dose in Japanese type 1 diabetic patients who use the insulin pump.