Objectives: In the management of diabetic patients on insulin therapy, adherence to medication is a key element for avoiding chronic complications. The purpose of this study was to evaluate diabetic patients' ability to translate glycemic results into an appropriate insulin dose and thus, adherence to insulins.Methods: This was an observational, retrospective, monocentric pilot study. Diabetic patients on insulin therapy being followed at the metabolic and endocrine diseases department were divided into two groups depending on their mode of glycemic control at home: capillary glycemia (Notebook group) or interstitial glycemia using the FreeStyle Libre® flash system (FSL group). Adherence was assessed based on the rate of compliance in adapting insulin doses to the prescribed protocols (depending on type of insulin, glycemic targets, and patients' characteristics) by a pharmacy resident and a senior diabetologist. Good adherence was defined as a minimum rate of 80% of conforming insulin injections for each patient.Results: A total of 50 patients were included, 35 in the Notebook group and 15 in the FSL group. Two-thirds of patients were non-adherent to insulin. Dose adjustment errors mainly concerned rapid-acting insulin with 51.1% of non- conformities, 10.0% of which were due to underdosing in the Notebook group and 21.7% to overdosing in the FSL group. Hyperglycemia was predominant in both populations with a median time in range of 19.0% in the FSL group and well below recommendations (>70%).Conclusions: Despite the use of increasingly efficient, easy-to-use devices in diabetes monitoring, insulin non-adherence and glycemic imbalance are unresolved major issues. Diabetic patients require reinforced medical follow-up for optimal insulin management.