Chronic hyperglycemia is an important cause for the development of chronic complications of diabetes, but glycemic variability has emerged in recent years as an independent contributor to diabetes-related complications. Our objective was to evaluate glycemic variability in patients with T2DM treated with insulin compared with other antidiabetic drugs. In this retrospective study, we collected 24-hour continuous glucose monitoring (CGM) recording data from 95 patients with T2DM, of which 27 treated with insulin and 68 with non-insulin treatment. We calculated and compared 16 glucose variability parameters in the insulin-treated and non-insulin treated groups. Insulin treated patients had significantly higher values of parameters describing the amplitude of glucose value fluctuations (standard deviation of glucose values, percentage coefficient of variation [%CV], and mean amplitude of glycemic excursion [MAGE], p <0.05) and time-dependent glucose variability (percentage of time with glycemic values below 70 mg/dl and continuous overall net glycemic action [CONGA] at 2, 4 and 6 hours, p <0.05). In conclusion, insulin therapy in T2DM is correlated with significantly higher glycemic variability.