Abstract Growing teratoma syndrome (GTS) is a rare complication of malignant ovarian germ cell tumors. A 52-year old woman was admitted to our Gynecological Oncology Department with metastatic multiple abdominal masses. Her initial gynecological history presented an immature teratoma of the ovary 3 years previously, and she underwent total abdominal hysterectomy, bilateral salpingo-oophorectomy, bilateral pelvic-paraaortic lymphadenectomy and omentectomy. She received three cycles of bleomycin, etoposide and cisplatin (BEP) regimen after surgery. Although the tumor markers were within normal limits, multiple metastatic lesions were detected in the 3rd month of follow-up. The patient was referred to our gynecological oncology department, optimal debulking including resection of the tumoral lesions localized on the liver, diaphragm, peritoneum, sigmoid colon, omentum and retroperitoneum was performed. Histopathology of all samples revealed mature teratoma. This syndrome should be remembered when a tumor is refractory to chemotherapy and growth of the tumor still continues after resection of the initial tumor.