Lupus anticoagulants have been recognized as significant causes of morbidity in patients for many years. They were originally regarded by physicians and researchers as a nuisance. However, the name is a misnomer that has resisted change over the years. The riddle of the anticoagulant effect in vitro and the apparent procoagulant effect in vivo remains unsolved. Since a lupus anticoagulant can exist in virtually every patient population, it is no longer a topic of interest limited only to the hematologists, but has achieved multidisciplinary attention. The presence of a lupus anticoagulant should be evaluated in any patient who presents with new onset transient ischemic attack or cerebral vascular accident, unexplained deep venous thrombosis, or recurrent fetal wastage.