Paroxysmal nocturnal haemoglobinuria (PNH) is a rare, acquired, life-threatening haematological disorder. It is characterised by complement induced haemolytic anaemia, thrombosis and impaired bone marrow function. Thrombosis most commonly occurs in the hepatic, portal, superior mesenteric and cerebral veins. A22-year female, previously diagnosed with severe aplastic anaemia treated with anti-lymphocyte globulin (ALG) and cyclosporine, had become transfusion independent for more than 10 years. She presented with abdominal pain and vomiting, initially diagnosed with portal and superior mesenteric vein thrombosis. Immunophenotyping by flow cytometry revealed a diagnosis of paroxysmal nocturnal haemoglobinuria type III. She was treated with vitmamin K anatagonist and platelet transfusion.