Abstract： bjective To compare the clinical efficacy and safety of once-daily 60 mg of slow-（released） gliclazide（China Associate Pharmaceutical Co.LTD） with twice-daily of gliclazide（（160 mg/d）） in the treatment of Chinese patients with type 2 diabetes mellitus（T2DM）.Methods 234 Chinese patients with T2DM meeting 1997 WHO diagnostic criteria were recruited from 4 clinical centers.The patients were assigned to slow-released gliclazide（117 case） or gliclazide（117 cases） treatment group in a ramdomized,double blinded,multicentre clinical trial.The trial consisted of 2-weeks wash followed by 12-week treatment period.Results Compared with the baseline,HbA1c,fasting and postprandial plasma glucose levels were significantly reduced in two groups after 12-week treatment.In slow-released gliclazide group,the mean reductions of blood HbA1c,fasting and postprandial plasma glucose levels were 0.81%,1.91 mmol/L and 2.41mmol/L respectively;in gliclazide group,the mean reductions of blood HbA1c,fasting and postprandial plasma glucose levels were 0.76%,1.97mmol/L and 2.13 mmol/L respectively.The differences in the reduction rates of fasting and postprandial plasma glucose levels between the two groups were not statistically significant.No serious adverse events in two groups were found;no laboratory-proved hypoglycemia（plasma glucose≤2.78 mmol/L） was observed.Conclusion Oncedaily 60 mg of slow-released gliclazide provides an effective control of plasma glucose levels for Chinese T2DM patients.Compared with twice-daily of gliclazide（160 mg/day）,slow-released gliclazide is equally well safe and effective