This study was performed to examine the efficacy and safety of mitiglinide in type 2 diabetes patients (T2DM). Enrolled patients had received treatment with diet and exercise in the previous 3 months with glycosylated haemoglobin (HbA1c) 7-10%, and were randomized to receive mitiglinide (n = 111, 5-20 mg/meal) or nateglinide (n = 114,60-120 mg/meal) for 16 weeks. Primary and secondary efficacy endpoints were assessed by the changes in HbA1c, fasting blood glucose (FBG) and postprandial glucose (PBG) levels. The baseline HbA1c value was 8.2 and 8.3% in both groups. At the end of study, the reduction of HbA1c values from baseline by mitiglinide was slightly more than that by nateglinide (-1.11% vs. -0.76%), but not statically significant (p = 0.06). Final FBG and PBG were comparable for the two treatments. There were 2.8% subjects treated with nateglinide who had hypoglycaemic episodes, but none in the mitiglinide treatment group. The results indicate that mitiglinide and nateglinide had similar effects on FBG, PBG and HbA1c in T2DM patients after the 16-week treatments.