Primary: To characterize the safety of RIXUBIS when used under normal clinical care in South Korea.

Secondary: To describe hemostatic effectiveness in subjects receiving RIXUBIS under normal clinical care in South Korea.

Inclusion Criteria:

1. Participants with congenital hemophilia B (FIX level ≤5%)
2. Participant or the participant's legally authorized representative has provided signed informed consent.
3. Participant is indicated for treatment according to the RIXUBIS Korean product leaflet.

Exclusion Criteria:

1. Participants with known hypersensitivity or presence of any contraindication to RIXUBIS or its excipients including hamster protein
2. Participants with Disseminated Intravascular Coagulation (DIC)
3. Participants with signs of fibrinolysis

Patients with hemophilia B in South Korea who have been prescribed RIXUBIS.

Takeda provides access to the de-identified individual participant data (IPD) for eligible studies to aid qualified researchers in addressing legitimate scientific objectives (Takeda's data sharing commitment is available on https://clinicaltrials.takeda.com/takedas-commitment?commitment=5). These IPDs will be provided in a secure research environment following approval of a data sharing request, and under the terms of a data sharing agreement.

IPD from eligible studies will be shared with qualified researchers according to the criteria and process described on https://vivli.org/ourmember/takeda/. For approved requests, the researchers will be provided access to anonymized data (to respect patient privacy in line with applicable laws and regulations) and with information necessary to address the research objectives under the terms of a data sharing agreement.