The catastrophic antiphospholipid syndrome (CAPS) is rare and usually fatal. In this report, we describe an unusual patient who, 31 years after experiencing an atypical preeclampsia-eclampsia presentation known today as the HELLP syndrome (hemolysis, elevated liver enzymes, and low platelets), developed CAPS, which seemed to complicate a diagnosis of primary antiphospholipid syndrome. She responded to repeated plasmapheresis over 3 years. Anticoagulants, corticosteroids, intravenous gamma globulin, and intravenous cyclophosphamide had all failed to halt the progression of CAPS, but repeated plasmapheresis not only halted the condition, but it led to the reversal of a leukoencephalopathy. The relationship between HELLP syndrome and CAPS is discussed, and possible pathogenetic mechanisms that explain the efficacy of repeated plasmapheresis in this setting are suggested. It is postulated that perhaps plasmapheresis, through removal of cytokines or other mediators, disrupts the interaction between phospholipid-protein complexes and endothelial cells. Repeated plasmapheresis should be considered in the most refractory cases of CAPS when more conventional treatment regimens have failed.