OBJECTIVE The purpose of this clinical investigation was to evaluate the frequency, clinical presentation, evolution, and maternal-fetal morbimortality of Acute Fatty Liver of Pregnancy (AFL). MATERIAL AND METHODS Over a period of 7 years from January 1990 to December 1996 the charts of patients with diagnosis of Gestational Acute Fatty Liver released from the Adult Intensive Care Unit of the Hospital Luis Castelazo Ayala of the Instituto Mexicano del Seguro Social were examined. The following information was retrieved: presenting symptoms, diagnosis on admission to the hospital and intensive care unit, evolution, laboratory, paraclinical, biopsy and serological findings, complications in mother and child, management and method of terminating pregnancy. RESULTS Twelve cases of AFL of Pregnancy were detected. The disease was not suspected on hospital admission in the majority of the cases; all sought attention because of an obstetric complication requiring termination of pregnancy such as acute fetal distress or rupture of membranes. The average age of the patients was 25 years with an average gestational age of the fetuses of 36 weeks. Symptoms were presented one to seven days and consisted of jaundice in 100% of the cases, systemic hypertension in 75%, abdominal pain in 67%, nausea and vomiting in 50%, preeclampsia in 41% and consciousness disturbances in 17%. Outstanding laboratory findings included TGO 57 +/- 108 U/L, TGP 53 +/- 114 U/L, hypocholesterolemia 79 +/- 30 mg/dL, total bilirubin 15.6 +/- 7 mg/dL, coagulation times prolonged almost two fold, leukocytosis, thrombocytopenia of 41,883 +/- 24,352 mm3, hypoglycemia of 51 +/- 16 mg/dL, and serum creatinine of 2.8 +/- 1.7 mg/dL. Ultrasound was performed in all patients but showed no specific alterations. CT scans on four patients demonstrated positive evidence in. Liver biopsies were performed on seven patients. The principal complications were DIC, hypoglycemia, acidosis, acute kidney failure, encephalopathy, three still births and one maternal death. CONCLUSIONS AFL of Pregnancy should be suspected in pregnant patients in third quarter who present jaundice, nausea and vomiting and abdominal pain with an obstetric complication such as acute fetal distress or rupture of membranes with symptoms of preeclampsia and laboratory evidence of hypoglycemia and thrombocytopenia. Intensive Care unit treatment and pregnancy solution are diminishing keys for maternal-fetal morbimortality rates and complications.