Abstract: Objective: To evaluate the efficiency and safety of Nateglinide in the treatment of type 2 diabetes mellitus.Methods: A multi-centre,double-blind,controled trial was conducted on 239 patients with type 2 diabetes mellitus,119 of whom（group A） received Nateglinide 120mg tid for 12 weeks.The other 120 patients（group B） were given Repaglinide 1.0 mg tid as controls.Parameters of therapeutic effects（HbA1c,blood glucose,insulin and body weight） were compared with that before the treatment.Results: The patients who had been treated with either Nateglinide or Repaglinide showed significant decrease on average from baseline in HbA1c（P＜0.01）,fasting plasma glucose（FPG,P＜0.01 and 0.05,respectively）,and postprandial plasma glucose at 1 and 2 hour（PPG1,PPG2,P＜0.01）.Nateglinide had stronger effect on reducing HbA1c and FPG than Repaglinide（P＜0.05 and 0.01,respectively）but more hypoglycemia in the former.The postprandial insulin levels at 1 and 2 hour（INS1,INS2） increased significantly in both groups（P＜0.01）and so was the body weight.Conclusion: Nateglinide and Repaglinide are both efficient,safe and well-tolerated drugs in the management of type 2 diabetes mellitus with better effect on reducing HbA1c and FPG.