A 38-year-old woman with metastatic malignant struma ovarii, including massive liver metastases and retroperitoneal lymphadenopathy, underwent ovarian resection and retroperitoneal lymph nodes excision, partial hepatectomy, and radiofrequency ablation for liver metastases. She underwent thyroidectomy and received three I treatments using recombinant human thyrotropin stimulation and radioiodine dosimetry. posttherapy I imaging, anatomic images, and thyroglobulin levels showed significant diminution in the tumor burdens and remarkable decline in thyroglobulin levels. This case provided valuable information on recombinant human thyrotropin-assisted I ablation in conjunction with dosimetry in an unusual presentation of iodine-avid malignant struma ovarii with bulky metastases.