AbstractA 27‐year‐old woman, gravida 1, para 0, was transferred to our hospital with acute abdominal pain. Her serum human chorionic gonadotropin level was 60 231 mIU/mL. Transabdominal ultrasound revealed an echo‐free space, and emergency laparoscopy‐assisted surgery was performed with a preoperative diagnosis of ruptured ectopic pregnancy. The pelvic cavity was filled with clots, and the peritoneal surface of the uterine fundus was swollen and showed continuous bleeding. The lesion was located on peritoneum and not connected with the uterine cavity. Histological examination of the conceptus showed features of a complete hydatidiform mole. After a mild decrease, hCG levels adversely increased 3 weeks later with multiple lung nodules. With a diagnosis of invasive moles, the patient was administered chemotherapy. This case demonstrates that it is important to recognize the potential of ectopic hydatidiform moles through abdominal pregnancy. This is the first report of an invasive abdominal hydatidiform mole, and hCG monitoring seemed to be essential for gestational trophoblastic neoplasia detection.