Post-marketing Surveillance (Use Result Surveillance) With Refixia®

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 Refixia® 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. At each site of this study, all patients will be registered consecutively from the first patient after the launch of Refixia® (consecutively registered system). * Diagnosis of haemophilia B in males or females, no age limitation. Patients younger than 12 years old will continue to be registered for 3 years of recruitment period regardless of the target number of patients. * New patients who have not been previously exposed to Refixia®. Also patients previously exposed to Refixia® in NN7999-3639, -3747, -3774, -3775 or -3895 clinical trial can be enrolled in this study. The patients who have participated in NN7999 -3774 or -3895 clinical trial can be enrolled in this study as continuous cases until 30-September-2024 (one year before planned end of study date). Exclusion Criteria: * Previous participation in this study. Participation is defined as having given informed consent in this study * Mental incapacity, unwillingness or language barriers precluding adequate understanding or cooperation * Known or suspected hypersensitivity to study product or related products.