Rhabdomyosarcoma arising in abdomen and pelvis is an uncommon but important type of soft tissue sarcoma, posing a great challenge for clinicians. Sporadic cases of intra-abdominal rhabdomyosarcoma were reported, but mostly in pediatrics. We demonstrated a rare case of primary abdominopelvic rhabdomyosarcoma in an elderly woman who presented with a notable increase in abdominal circumference and constipation. Abdominal magnetic resonance imaging showed a huge mass throughout the abdomen and pelvis. Cytoreductive surgery was performed by gynecologists due to the suspicious diagnosis of disseminated leiomyosarcoma. However, the final pathological analysis revealed embryonal rhabdomyosarcoma. Although adjuvant chemotherapy was administered, localized recurrence was identified 6 months after the initial operation. Gynecologists and radiologists should be aware of it so it can be listed in the differential diagnosis of masses that primarily arise in the abdomen and pelvis.