Abstract: Objective: To investigate the effect and safety of nateglinide in treatment of patients with type 2 diabetes mellitus.Methods: A randomized double blind control trial was followed up for twelve weeks.Forty-eight selected cases were randomly divided into two groups in the ratio of one to one:observation group (nateglinide) and control group (repaglinide).The 2 hours plasma glucose(2hPG) and HbAlc levels of the patients were observed.Results: 2hPG and HbAlc levels of the two groups decreased obviously after treatment(P<0.01).The decreasing levels of 2hPG and HbAlc of each group' had no obvious differences (P>0.05).Conclusions: Nateglinide is effective and safe for the treatment of type 2 diabetes mellitus with slight side effects.