Hemophilia A is classically caused by a congenital deficiency of factor VIII, but an acquired form due to inhibitors to factor VIII (FVIII) typically presents later in life. Patients who develop such acquired factor VIII inhibitors may present with catastrophic bleeding episodes, despite having no prior history of a bleeding disorder. Though the disorder is rare, it is known to cause significant morbidity and mortality. This review will focus on what is currently known about acquired hemophilia A, its pathogenesis, its associated etiologies, and its treatment.