Objective: We sought to describe our experience with the clinical diagnosis, management, and course of patients with acute fatty liver of pregnancy. Study Design: Twenty-eight cases of acute fatty liver of pregnancy at the Los Angeles County and University of Southern California Medical Center from 1982 to June 1997 were identified, and presenting symptoms, clinical course, laboratory values, maternal complications, and neonatal outcomes were studied. Results: The incidence of acute fatty liver of pregnancy was 1 in 6659 births. There were no maternal deaths. Initial presentation was at an average of 37 weeks of gestation with a characteristic prodrome of malaise, nausea, vomiting, and abdominal pain. No patient was admitted with the diagnosis of acute fatty liver of pregnancy. The condition was diagnosed most commonly on the second hospital day after laboratory results indicated coagulopathy, renal insufficiency, and liver function abnormalities. One patient underwent liver biopsy at cesarean delivery. Radiologic studies did not aid with the diagnosis. Twenty-one patients were admitted in spontaneous labor, and 16 labors were complicated by abnormal fetal heart rate patterns or meconium. There was 1 stillbirth and 1 neonatal death as a result of perinatal asphyxia. Maternal morbidity consisted of hypoglycemia, infection, renal insufficiency, coagulopathy, encephalopathy, and wound complications. All patients had evidence of disseminated intravascular coagulopathy with profoundly decreased antithrombin levels. All patients recovered normal liver function post partum. Conclusions: Reversible peripartum liver failure may be diagnosed and managed on the basis of clinical and laboratory criteria. With adequate support, these patients may have full recovery of hepatic function. (Am J Obstet Gynecol 1999;181:389-95.)