This study is conducted in Asia. The aim of the study is to evaluate long term safety and efficacy of Tresiba® (insulin degludec) in patients with diabetes mellitus in routine clinical practice in India.

Inclusion Criteria:

• Informed consent obtained before any study-related activities (Study related activities are any procedure related to recording of data according to the protocol). The historical data including the data before informed consent obtained (e.g. glycosylated haemoglobin (HbA1c), fasting plasma glucose (FPG), severe hypoglycaemia before the start of Tresiba® therapy) can be used for baseline data
• Patients with insulin requiring diabetes mellitus and who is scheduled to start treatment with Tresiba® based on the clinical judgment of their treating physician

Exclusion Criteria:

• Known or suspected allergy to Tresiba®, the active substance or any of the excipients
• Previous participation in this study
• Mental incapacity, unwillingness or language barriers precluding adequate understanding or cooperation
• Patients who are or have previously been on Tresiba® therapy
• Patients who are participating in other studies or clinical trials
• Patients who are pregnant, breast feeding or have the intention of becoming pregnant within the following 12 months

Patients with diabetes mellitus requiring insulin therapy who qualify for starting treatment with Tresiba® based on the clinical judgment by their treating physician during enrolment period.