This is a 36-month, long-term, multicenter, observational study designed to describe the real world effectiveness of pegcetacoplan in patients with PNH. Patients meeting the eligibility criteria will be enrolled in the study and followed prospectively for approximately 36 months. Patient data will be collected from start of pegcetacoplan treatment to end of follow-up. Retrospective data on pegcetacoplan will be captured from the time of pegcetacoplan treatment initiation. Pegcetacoplan treatment data will be collected for a minimum of approximately 36 months and up to a maximum of approximately 72 months, including retrospective period depending on when the patient started pegcetacoplan treatment. After pegcetacoplan treatment discontinuation, patients will remain in the study for 8 weeks to capture any AEs. The scope of the study is to collect both retrospective and prospective data. Baseline is defined as start of pegcetacoplan treatment. The main part of the study will be prospective,collecting data on effectiveness, safety (all AEs), patient- and clinician-reported outcomes and health care resource use.