s u m m a r y Background: Basal insulin is a common therapy for insulin initiation in patients with type 2 diabetes mellitus (T2DM) uncontrolled with oral antidiabetic drugs (OAD). There is limited data for initiating basal insulin therapy in the elderly population in clinical practice. Methods: The aim of this study was to analyze 72 Taiwanese patients with T2DM on OAD with glycated hemoglobin (HbA1c) > 7% who received basal insulin therapy with insulin glargine for 24 weeks in clinical practice. The patients were divided into an older group (! 65 years, n ¼ 32) and younger group (< 65 years, n ¼ 40) for comparison purposes. Results: At baseline, the duration of diabetes was longer and the fasting plasma glucose (FPG) level was slightly lower in the older group versus the younger group. The number of OAD types was significantly reduced after initiation of basal insulin in both groups. After the 24-week treatment of insulin glargine, the HbA1c and the FPG were significantly reduced by 1.18% and 81.3 mg/dL, respectively, in the older group, and by 1.49% and 93.0 mg/dL, respectively, in the younger group, but did not differ statistically between the two groups. The mean daily insulin doses in both groups were similar. Body weight increased significantly but it was comparable in older and younger patients. The rate of hypoglycemic events was low and no difference was found between the two groups. Conclusion: In elderly people with T2DM in Taiwan who had inadequate glycemic control by OAD, initiation of basal insulin therapy with insulin glargine over 24 weeks provided effective glycemic control similar to the younger population.