Dysgerminoma is the most common malignant germ cell tumor of the ovary. It can be found either in a pure form or mixed with other germinal elements. It has also been reported arising from gonadoblastoma, which may be regarded as an in situ germ cell malignancy. We describe the case of an 18-year-old patient who had a dysgerminoma arising from the left ovary and a gonadoblastoma replacing the right ovary. She was a nonvirilized phenotypic female, with 46, XY genotype. The patient underwent bilateral salpingo-oophorectomy with total hysterectomy, appendicectomy, infracolic omententectomy, selective pelvic and para-aortic lymphadenectomy, peritoneal random biopsies. The surgical-pathological stage of dysgerminoma was retroperitoneal stage III. The patient received postoperative radiotherapy on the whole pelvis and para-aortic lymph nodes and precautional radio therapy on the mediastinum and supraclavicular lymph nodes. She is currently alive with no evidence of disease after 46 months from surgery.