The effects of orally administered dipeptidyl peptidase IV (DPP-IV) inhibitor on the glucose-lowering effect of glibenclamide are still unknown. We evaluated the effects of combination treatment with a long-lasting DPP-IV inhibitor, K579 ((S)-1-[4-methyl-1-(2-pyrimidinyl)-4-piperidylamino]acetyl-2-pyrrolidinecarbonitrile), and glibenclamide on the glycemic responses to glucose loading in rats. Treatment with K579 inhibited the plasma DPP-IV activity even 8 h after the administration. K579 significantly suppressed the blood glucose elevation in glibenclamide-pretreated rats without excessive hypoglycemia. These profiles of K579 indicate that it could be useful agent to correct the postprandial glucose excursion in type 2 diabetes patients by combination treatment with glibenclamide.