Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired disorder characterized by intermittent hemolytic anemia. High-dose methylprednisolone (HDMP) was administered in two patients, eight- and 16-year-old females, with PNH. This drug produced a dramatic improvement in the hemoglobin level, leukocyte and platelet counts. No side effect was observed in either patient during the treatment period. The patients were followed up on an outpatient basis for six and 16 months. In conclusion, HDMP therapy for PNH appears to be more effective and safe than previously reported therapies.