Postprandial hyperglycaemia and spikes have deleterious effects on Insulin secretion and sensitivity. The present study was undertaken to evaluate the efficacy, safety and tolerability of miglitol 50 mg three times daily for 12 weeks in 129 patients with type 2 diabetes mellitus, inadequately managed with diet and exercise therapy alone for 3 months after obtaining their written informed consent. The primary efficacy variables were per cent change from baseline at week 12 in fasting and postprandial plasma glucose concentrations and glycosylated haemoglobin (HbA(1C)) levels. After treatment at the end of 12 weeks mean reduction in fasting plasma glucose levels was 35.7% and 44.33% in postprandial plasma glucose levels while the mean HbA(1C) was significantly reduced by 0.88% (p<0.05). Total cholesterol, HDL, LDL and TC/HDL ratio did not showed any significant change but a non-significant reduction in triglyceride levels was observed in some patients. The mean body mass index was reduced non-significantly by 8% from baseline values. A total 19.5% patients treated with miglitol reported adverse events like flatulence, abdominal pain, nausea/vomiting, diarrhoea and dyspepsia. Only one patient reported hypoglycaemia. The results of the present study indicate that miglitol reduces fasting and postprandial plasma glucose levels, Improving glycaemic control, which is reflected in a reduced HbA(1C) level in patients with type 2 diabetes mellitus. It could be a useful first-line therapy in patients with type 2 diabetes mellitus inadequately controlled by diet alone and as adjuvant therapy in patients who are inadequately controlled with diet and sulfonylureas.