Background/Objectives: This analysis was conducted in Italy to estimate the epidemiology of paroxysmal nocturnal hemoglobinuria (PNH) and to describe the features and economic burden of PHN in the adult population considering the role of anti-complement therapy with C5/3-inhibitors (C5/3i). Methods: Administrative databases of healthcare entities covering approximately 12 million citizens were used to estimate the prevalence and incidence of PNH. Demographics, clinical characteristics and healthcare costs were analyzed among adults with PHN stratified by the presence/absence of C5/3i therapy. Results: The prevalence in Dec-2021 of PNH in adults was 17.6/1,000,000 people, and the incidence rate in the period 2011–2022 was 1.5/1,000,000/year. In 142 patients with at least 12 months of data available before and after inclusion (mean age: 50.7 years; 45.8% males), 27% received C5/3i therapy. The main baseline comorbidities were aplastic anemia and other bone marrow failure syndromes, found in 10.6% of patients and more common in C5/3i-treated than untreated patients (18.4% vs. 7.7%). Cost analysis showed that the average cost per patient per year (PPPY) was EUR 41,084, mainly driven by drug expenses (87% of total costs), especially anti-complement therapy (80%). RBC transfusions were the most impactive item among the hospitalization costs (EUR 1982 of EUR 4284 PPPY). The C5/3i-treated cohort was associated with higher total costs (EUR 133,472 vs. EUR 8089, p < 0.001), mainly due to drug expenses (EUR 127,180 vs. EUR 3217, p < 0.001). Conclusions: This real-world analysis confirmed a rising PNH prevalence in Italy, aligning with global data. Despite available therapies, many patients face a high disease burden, suggesting potential benefits from novel treatments targeting upstream complement components.