Placental abruption is defined as the early separation a normal placenta from the wall of the uterus before delivery of the fetus. The incidence of it is known 1% of all pregnancies and perinatal mortality rates from abruption range from 20% to 40% in recent studies. The most common symptom is vaginal bleeding. The causes are associated with preeclampsia, other hypertensive disorders, and premature rupture of membranes. It is diagnosed by clinical symptom, sign, and ultrasonography. Recently we have experienced a case of placental abruption diagnosed at 31 weeks by ultrasonography in bicornuate uterus with a brief review of the literature.