Eighty-two newly-diagnosed type 2 diabetic patients with poor glycemic control were treated by mitiglinide calcium for 16 weeks.Plasma fibroblast growth factor-21 ( FGF-21 ) level were evaluated.The relationship of plasma FGF-21 levels with body mass index,body fat,waist-to-hip ratio,lipid,blood glucose,HbA1c,and free fatty-acid were analyzed.Plasma FGF-21 was decreased significantly by treatment with mitiglinide calcium in type 2 diabetic patients,and it may play a role in the pathogenesis of type 2 diabetes mellitus.