A 41-year-old woman had a uterine rupture at the 15th week of pregnancy caused by an undiagnosed intramural pregnancy. She had previously been misdiagnosed with an intrauterine pregnancy and had an intrauterine evacuation device (IUD) inserted. After 9 weeks, there was sudden distension of the lower abdomen, ultrasound showed a fetus without cardiac activity in the peritoneal cavity and rupture of the uterine fundus. Emergency laparotomy revealed 1700 mL of hemoperitoneum, a free fetus with envelopes, and a 3.5 × 3.0 cm uterine defect with active bleeding that did not communicate with the uterine cavity. The fallopian tubes and ovaries were normal, the dead fetus with amniotic sac was removed, the uterus was repaired with absorbable suture, and the estimated blood loss was 1800 mL. The patient recovered well and was discharged. Intramural pregnancy should be considered in women with uterine trauma, persistent IUD pregnancy, and ineffective evacuation.