BACKGROUND : Idiopathic non-cirrhotic portal hypertension (INCPH) is mainly associated with thrombophilia in Western countries. Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematologic disease that manifests with hemolytic anemia, thrombosis, and peripheral blood cytopenias. Portal and hepatic venous thrombosis were reported in PNH. A rare case of INCPH complicating PNH is described. METHODS : A 63-year old woman with a 2-year past medical history of PNH without treatment was admitted because of jaundice and refractory ascites requiring large volume paracentesis. Liver histology revealed portal venopathy with portal fibrosis and sclerosis, nodular regenerative hyperplasia, parenchymal ischemic changes, and focal sinusoidal and perivenular fibrosis without bridging fibrosis or cirrhosis, all indicative of INCPH. The flow cytometry confirmed PNH diagnosis and eculizumab treatment was initiated. Her condition was improved gradually, bilirubin was normalized 6 months following initiation of eculizumab, and 1 year later diuretics were stopped. CONCLUSIONS : Eculizumab improved intravascular hemolysis and reversed clinical manifestations of INCPH in a patient with paroxysmal nocturnal hemoglobinuria.