Didelphys uterus results from an incomplete fusion of mullerian ducts and corresponds to the class III of mullerian abnormalities of the American Fertility Society. We describe the case of a spontaneous twin pregnancy developed in each cavity of a didelphys uterus. At 29 weeks of gestation and 6 days, the patient had preterm rupture of membranes in the right horn. She went into spontaneous labor and delivered vaginally the first “right” twin. Delivery was complicated with post-partum hemorrhage on uterine atonia treated with a Bakri balloon. She was tocolyzed to pursue the fetal lung maturity of the second twin. She had a rupture of the second membranes at 30 weeks and 3 days and had a preterm vaginal delivery at 32 weeks and 1 day of the second twin. Twin pregnancy in both horns of a uterus is extremely rare, about 1 in 1,000,000. Pregnancies on congenital abnormalities of the paramesonephric duct present frequently poor obstetrical outcomes and many complications. There are no guidelines about the follow-up of these high-risk patients or the mode of delivery.