Recurrent pregnancy loss (RPL) is the loss of 3 or more spontaneous and consecutive pregnancies. There are many causes, such as genetic, anatomic, hormonal, medical and immunologic causes. Two theories, the alloimmune and the autoimmune theories, explain the immunologic cause. The Antiphospholipid Antibody (APA) Syndrome is considered as the autoimmune cause of RPL. It involves two antibodies, Lupus anticoagulant (LAC) and the anti-cardiolipin antibody (ACA). The rate of LAC is 7% and of ACA is 15%, among pregnant women. These two antibodies are believed to cause thrombosis in the maternal circulation, leading to the events that lead to the fetal losses. Women with these antibodies, along with other factors, are believed to be at high risk for RPL. The diagnostic criteria for the APA syndrome include elevated LAC or ACA serum levels and clinical findings of thrombosis, thrombocytopenia and RPL. Presently, the medical treatment of the APA syndrome includes heparin, low-dose aspirin, and immunoglobulins. There must also be an active attempt to search for other causes of RPL among patients with APA syndrome, such as anatomic, endocrinologic, anatomic and medical problems. Management of RPL should also include extensive counseling for the patient and her family.