Background <p>Uterus didelphys, or“double uterus,”is caused by the failure of Müllerian ducts fusion, eventually forming two uterine cavities, and it is one of the rare uterine malformations.Uterus didelphys and twin pregnancies are extremely rare clinically. In this paper, we report a case of twin pregnancy with uterus didelphys, simultaneous spontaneous conception with bilateral uterus and 12 weeks’ interval of delivery. It also reviews the relevant literature to discuss the characteristics of fertility in patients with uterus didelphys and reasonable obstetric management.</p> Case presentation <p>A 26-year-old patient with a uterus didelphys was presented to the emergency department at 25⁺⁶ weeks pregnancy with intermittent lower abdominal pain from last 1&#xa0;h. On the second day of admission, male infant was delivered naturally through the right side of the uterus. After 12 weeks, the woman’s amniotic fluid broke and a female infant was born on the left side of the uterus. The mother was healthy and was discharged safely.</p> Conclusions <p>The incidence of simultaneous pregnancy in uterus didelphys is low and extremely rare. For patients who see a doctor for the first time, the clinician should ask the patient’s maternity history in detail to improve the level of the clinician’s specialist examination. In general, the fetus in uterus didelphys pregnancy is limited in intrauterine growth, and the survival rate is low. After treatment, the gestational age is prolonged and the fetal growth is promoted. At the same time, the uterine condition is closely monitored to prevent uterine rupture.</p>