A Study to Evaluate Safety and Effectiveness in Patients of All Age Groups Excluding Less Than 12 Months Old Infants With Diabetes Mellitus in Routine Clinical Practice in Korea

Inclusion Criteria: - Signed consent obtained before any study-related activities (study-related activities are any procedure related to recording of data according to the protocol) - The decision to initiate treatment with commercially available Tresiba® FlexTouch® has been made by the patient/Legally Acceptable Representative (LAR) and the treating physician before and independently from the decision to include the patient in this study - Male or Female, Age at least 12 months, at the time of signing informed consent with type 1 or type 2 diabetes mellitus and who is scheduled to start treatment with Tresiba® FlexTouch® based on the clinical judgment of their treating physician as specified in the Korean-Prescribing Information (KPI) Exclusion Criteria: - Previous participation in this study. Participation is defined as having given informed consent in this study - Patients who are or have previously treated with Tresiba® FlexTouch® - Mental incapacity, unwillingness or language barriers precluding adequate understanding or cooperation. However, paediatric patients can be enrolled when the patient's primary caregiver (e.g. parents) or legally acceptable representatives (LAR) are capable of giving study specific signed informed consent. Any chronic disorder or severe disease which in the opinion of the investigator might jeopardise patient's safety or compliance with the protocol - Female who is pregnant, breast-feeding or intends to become pregnant and is of child-baring potential and not using adequate contraceptive methods (adequate contraceptive measures as required by local regulation or practice)