OBJECTIVE To evaluate the efficacy and safety of gliclazide modified release (MR), alone or combined with other oral antidiabetic drug(s) over 2 years in type 2 diabetic patients. METHODS Two consecutive periods: (i) a 10-month, double-blind comparative study, where 800 type 2 diabetic patients were randomized either to gliclazide MR (30-120 mg) once daily or to gliclazide (80-320 mg) twice daily. All the patients were then treated with gliclazide MR for a 2-month switch period; (ii) 549 patients were subsequently enrolled in a 12-month, open-label period on gliclazide MR alone or in combination according to glycaemic control, 507 of whom completed the study. RESULTS Glycated haemoglobin (HbA1c) significantly decreased from baseline over 2 years by -0.46 +/- 1.08% in the whole cohort of 2-year completed patients, -0.95% in the subgroup of diet-failed patients and by -0.34% in the subgroup of patients pretreated with one oral antidiabetic drug. HbA1c was reduced by -0.43 +/- 1.02% and by -0.51 +/- 1.16%, when gliclazide MR was used in monotherapy and in combination therapy, respectively. The overall incidence of symptoms suggestive of hypoglycaemia was 4.8 episodes/100 patient-year, with no severe episode. This incidence was similarly low in elderly patients and patients with impaired renal function. CONCLUSIONS Gliclazide MR alone or in combination with another oral antidiabetic drug significantly improved glycaemic control in type 2 diabetic patients over 2 years with a very good safety profile, notably in the elderly and in patients with impaired renal function.