We describe the case of a rudimentary horn pregnancy coexistent with an intrauterine pregnancy. This situation is usually associated with rupture of the rudimentary horn and death of the correspondent twin. This is the first report on a multiple gestation with the two siblings successfully delivered by caesarean section in the two horns of a unicornuate uterus with rudimentary horn before any complication. Since the maternal mortality is higher in this situation, early ultrasound diagnosis is important to make the right decisions.