Fifteen patients were identified in a retrospective analysis of one institution's experience with the use of tocolysis in selected patients with an admission diagnosis of placenta previa or abruptio placentae. There were no fetal deaths after admission, and the two neonatal deaths were related to prematurity. Eight of the 15 patients receiving tocolysis had their pregnancies prolonged by 2 weeks or more, and there were no fetal or neonatal deaths in this group. Both neonatal deaths occurred in patients who underwent tocolysis but who gave birth within 1 day of admission. These data suggest the safety of tocolysis in preterm patients with the diagnosis of placenta previa or abruption who are bleeding. A prospective, randomized trial is required to evaluate whether tocolysis is superior to expectant management or to immediate delivery. The clinical difficulty in differentiating between these two diagnoses, despite liberal use of ultrasonography, is discussed.