Aim The effect of rapid-acting insulin secretagogues (glinides) on glycemic control when included with insulin therapy for type 2 diabetes remains uncertain. To examine this, we added glinide once a day to twice daily injections of premixed insulin. Research Design and Methods Seventy-four type 2 diabetic patients, taking twice daily injections of premixed insulin and whose diabetic control was stable, were registered at 6 independent institutions. After a 3-month observation period, 60 patients were administered 10 mg mitiglinide or 90 mg nateglinide at lunchtime without changing their insulin regimen. After 12 weeks, administration of glinide was discontinued and observation was continued. HbA1c levels were measured at the start of glinide administration, after 12 weeks of glinide , and at 12 weeks after discontinuation. Results HbA1c improved from 7.72±0.66% to 7.55±0.71% (p <0.01) at Week 12 of glinide administration. Twelve weeks after discontinuation, HbA1c returned to the baseline level (7.72±0.81%). Conclusion This study indicates that the addition of glinide once a day at lunchtime to twice daily injections of premixed insulin is effective for the treatment of type 2 diabetes.