From 1978 to 1982, 70 cases of emergency hysterectomy for obstetric hemorrhage were performed at Los Angeles County/University of Southern California Women's Hospital. Sixty hysterectomies followed cesarean section, and ten were performed for hemorrhage after vaginal delivery. The most common indication for hysterectomy was atony (43%) followed by placenta accreta (307c), uterine rupture (13%), extension of a low transverse incision (10%), and leiomyomata preventing uterine closure and hemostasis (4%). Hysterectomies performed for atony had a significant association with the following factors when compared to hysterectomies performed for other indications: 1) amnionitis, 2) cesarean section for labor arrest, 3) oxytocin augmentation of labor, 4) MgSO4 infusion, and 5) fetal weight. Fifty-seven percent of hysterectomies performed for placenta accreta were associated with a previous cesarean section. During the study period, 53% of all patients presenting at term with both a placenta previa and one or more previous cesarean sections, subsequently underwent hysterectomy for placenta accreta. Even with a broad inclusion of risk factors, only 74% of patients developing a hemorrhagic complication leading to hysterectomy can be identified before delivery.