Ovarian immature teratoma is a malignant germ cell tumor and represents less than 1% of ovarian malignant tumors. Tissues are derived from the three germ layers (endo-, meso- and ectoderm). Tumor grading is based on the amount of immature neuroepithelium present. The prognosis is directly correlated to histologic grade. Rapid growth leads to large tumors with an early diagnosis. Therapeutic management is balanced between adjuvant chemotherapy and surgery alone. Nevertheless, as immature teratoma mostly occurs in young women, the main objective is to preserve fertility.