INTRODUCTION: Postpartum hemorrhage is an obstetrical emergency which requires aggressive volume repletion. Serum lactate levels are used in the management of trauma patients because they reliably indicate tissue hypoperfusion. METHODS: A retrospective chart review was performed from June 01, 2013 through Sept 30, 2016 in patients undergoing an Obstetric Hemorrhage Team (OHT) alert, defined at our institution as a quantified blood loss of 900 cc after vaginal delivery and 1500 cc after Cesarean section. Stat venous lactate levels were correlated with hematocrit levels, vital signs (BP and pulse), urine output, crystalloid fluid resuscitation and blood transfusion. RESULTS: There were 1314 OHTs. Of these, 891 patients had venous lactate values. When the venous lactate level was “elevated”, i.e. 4.0 (range 3.4 to 6.6), 632 patients (71%), required at least one unit blood transfusion in addition to the usual resuscitative measures, (statistically significant). Of these, only 347 patients (39%) were hemodynamically unstable (BP less than 60/40 and/or pulse rate greater than 120 bpm); and only 276 (31%) demonstrated a 10 point hematocrit drop from the admission value. When venous lactate levels were “normal”, i.e. 2.0 (range 1.6 to 3.2), only 80 (9%) required blood transfusions. CONCLUSION: Venous lactate is a reliable indicator of tissue hypoperfusion in postpartum hemorrhage, and may help to identify patients who, regardless of hemodynamic status or hematocrit level, would most benefit from blood transfusion during the management of this condition.