BACKGROUND Persistent cloacal malformations are rare anomalies that are anorectal malformations occurring in females. In cases of persistent cloaca, prenatal ultrasonography shows fetal ascites, cystic tumor in the abdomen, oligohydramnios, and hydronephrosis. There are various types of persistent cloaca, and symptoms vary. CASE REPORT A 38-year-old pregnant woman was referred to our hospital because of suspected fetal expansion of the intestinal tract. Prenatal ultrasonography revealed a fetal growth restriction, oligohydramnios, fetal abdominal cyst, and bilateral hydronephrosis, and persistent cloaca was suspected. Also, magnetic resonance imaging (MRI) revealed a double uterus and bilateral hydronephrosis, hydrocolpos; as such, persistent cloaca was diagnosed. Cesarean section was performed at 36 weeks+3 days gestation and delivered a female infant weighing 1957 g, with Apgar scores of 9 (1 min)/9 (5 min). CONCLUSIONS We report a case of persistent cloaca detected in the prenatal ultrasonography and MRI examination. Prenatal diagnosis is important because it can lead to a better outcome for infants with persistent cloaca. In the image inspection in persistent cloaca, there are characteristic findings such as ascites, cystic tumor in the abdomen, difficulty in visualizing the bladder, oligohydramnios, and hydronephrosis. So, if persistent cloaca is suspected, use of ultrasonography and MRI will allow its diagnosis.