PNH is a rare clonal hematopoietic stem disorder clinically characterized by the triad of chronic complement-mediated hemolysis, thrombosis, and bone marrow failure. While median survival has improved when historical data are compared to more recent data, thrombosis, the major cause of death in PNH, is still observed in approximately 40% of patients. The symptoms associated with this disorder–including fatigue, pain, esophageal spasm, and erectile dysfunction–are often severe and disabling. While PNH may be a curiosity to the physician, it forces the majority of patients to significantly modify their lives. Transplantation represents a curative option; however, the risks associated with this option are not insignificant. Eculizumab has been shown to significantly reduce hemolysis, improve anemia, reduce transfusion requirements, and significantly improve fatigue and other QoL scores. Clearly, targeted complement inhibition by eculizumab has the promise to significantly improve the lives of patients with PNH.