Locked twins usually occur when the after–coming head of the first beech fetus is locked with the head of the second cephalic fetus. A case of locked twins delivered by caesarean section is reported with one twin surviving. patient was an unbooked case and had undiagnosed twin pregnancy with head arrest of first twin in obstructed labour. . Fetal morbidity and mortality can be avoided in such situations by identifying the potential cases, radiological diagnosis and timely done caesarean section.