This study is conducted in Europe, and North and South America. The aim of this study is to provide additional documentation of the immunogenicity, and obtain additional clinical data, of turoctocog alfa in the setting of normal clinical practise in patients previously treated with a factor VIII agent (FVIII).

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
• Previously FVIII treated (150 exposure days at the time of first dosing with turoctocog alfa) male patients with the diagnosis of severe and moderately severe haemophilia A (FVIII below or equal to 2%)
• The decision to initiate treatment with commercially available turoctocog alfa has been made by the patient/parent and the patient's treating physician before and independently from the decision to include the patient in this study
• A negative FVIII inhibitor test obtained not more than four weeks prior to first dosing with turoctocog alfa

Exclusion Criteria:

• Contraindications for use according to the approved product information text (US Package insert (PI), European Summary of Product Characteristics (SmPC), or corresponding local prescribing information)
• Treatment with any investigational drug within 30 days prior to enrolment into the study
• Previous participation in any clinical trial with turoctocog alfa
• Treatment with other FVIII products after initiation of treatment with turoctocog alfa

Previously FVIII treated (more than 150 exposure days) patients with severe and moderately severe haemophilia A with FVIII below or equal to 2%.